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1 © Nokia Siemens Networks RN31679EN30GLA1
HSDPA RRM & parameters
2 © Nokia Siemens Networks RN31679EN30GLA1
HSDPA Principles
High Speed Downlink Packet Access (HSDPA) based on:• Node B decisions • Multi-code operation• Fast Link Adaptation
• Adaptive Modulation & Coding AMC• Fast Packet Scheduling• Fast H-ARQ• Fast 2 ms TTI*• Downwards Compatibility with R99
• (shared or dedicated carrier)
* TTI = 1 Subframe = 3 Slots = 2 msH-ARQ: Hybrid Automatic Repeat Request
Motivation:- enhanced spectrum efficiency- higher peak rates >> 2 Mbps- higher cell throughput- reduced delay for ACK transmission
3GPP Rel. 5; TS 25.308:
“HSDPA Overall Description”
3GPP Rel. 5; TS 25.308:
“HSDPA Overall Description”
•••up to 15 HS – Physical
DL Shared Channels
HSDPAenabledWCEL; 0 = disabled; 1 =
enabled
3 © Nokia Siemens Networks RN31679EN30GLA1
Principles of DC HSDPA
SSHSC
S1: TBS B
S1: TBS A
Primary serving cell
HS-SCCHHS-PDSCHF-DPCH (RAN1201)
E-DPDCHE-DPCCHHS-DPCCHDPCCH
HS-SCCHHS-PDSCH
• Dual-Cell HSDPA of 3GPP Rel8 uses two adjacent WCDMA carriers (same bandwidth) to transmit data for a single UE
• Can be used with MIMO 2x2 and/or 64QAM• DC HSDPA UEs are assigned HS-PDSCHs in the primary serving cell & Secondary Serving High Speed
Cell (SSHSC)• UL (CQI, ACK/NACK) for DC HSDPA UEs via primary serving cell (no UL in SSHSC)• Besides HS-DSCH the primary serving cell is carrying
– The full set of control & common control channels
– UL transport channels E-DCH HS-DPDCH + optional DC HS-DPCCH (HSUPA UEs)
• SSHSC is left clean from control signaling (max. HS-DSCH capacity)– Among common channels only CPICH is used in SSHSC
– E-AGCH, E-RGCH, E-HICH in SSHSC existent but not used by DC HSDPA
f1
f2
DCellHSDPAEnabledWCEL; 0 = disabled; 1 =
enabled
4 © Nokia Siemens Networks RN31679EN30GLA1
Adaptive Modulation & Coding (1/2)
I
Q0000
0010
0011
0001
1000
1010
1011
1001
1100
1110
1111
1101
0100
0110
0111
0101
16QAM
4-Bit KeyingQPSK
2-Bit Keying
Q
I
(1,1)(0,1)
(1,0)(0,0)
HSDPA uses• QPSK• 16QAM• 64QAM*dynamically based on quality of the radio link
* defined in 3GPP Rel. 7 / implemented with NSN RU20
5 © Nokia Siemens Networks RN31679EN30GLA1
Adaptive Modulation & Coding (2/2)
RateMatching
Puncturing /Repetition
RateMatching
Puncturing /Repetition
Turbo Coding1/3
Turbo Coding1/3
EffectiveCode Rate:
1/4 - 3/4
HSDPA Adaptive Coding• based on the R’99 1/3 Turbo Coding• Rate Matching: Puncturing or Repetition code rate: 1/6 – 4/4
• dynamically based on quality of the radio link
HSDPA Adaptive Coding• based on the R’99 1/3 Turbo Coding• Rate Matching: Puncturing or Repetition code rate: 1/6 – 4/4
• dynamically based on quality of the radio link
6 © Nokia Siemens Networks RN31679EN30GLA1
TURBO CODING
1) ¼ qpsk2) 2/4 QPSK3) ¾ QPSK4) 2/4 16QAM5) ¾ 16QAM6) 4/4 16QAM- 14.4Mbps7) ¾ 64QAM8) 5/6 64QAM9) 4/4 64QAM --- 21.6Mbps
7 © Nokia Siemens Networks RN31679EN30GLA1
C1,0 = [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]
C8,4 = [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
2 4 8 SF = 16
256 512...
SF = 16 240 ksymb/s
Multi-Code operation:
1..15 codes 0.24 .. 3.6 Msymb/s
SF = 16 240 ksymb/s
Multi-Code operation:
1..15 codes 0.24 .. 3.6 Msymb/s
Multi Code Operation (1/3)
8 © Nokia Siemens Networks RN31679EN30GLA1
Multi Code Operation (2/3)
RU20 includes3GPP Rel. 7 features:• 64QAM (RAN1643)
ModulationModulation
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 10.8 Mbps10.8 Mbps
4.8 Mbps4.8 Mbps 9.6 Mbps9.6 Mbps 14.4 Mbps14.4 Mbps
64QAM64QAM
3/43/4
5/65/6
4/44/4
5.4 Mbps5.4 Mbps 10.8 Mbps10.8 Mbps 16.2 Mbps16.2 Mbps
6.0 Mbps6.0 Mbps 12.0 Mbps12.0 Mbps 18.0 Mbps18.0 Mbps
7.2 Mbps7.2 Mbps 14.4 Mbps14.4 Mbps 21.6 Mbps21.6 Mbps
64QAM 6 bits/symbol
HSDPA64QAMAllowedWCEL; 0 (Disabled), 1 (Enabled)
9 © Nokia Siemens Networks RN31679EN30GLA1
UEIub
Uu
Re
du
ce
dre
tran
sm
iss
ion
Re
du
ce
dre
tran
sm
iss
ion
RNC:functionalities
shifted toNode B
RNC:functionalities
shifted toNode B
„more intelligence“new functionalities
new UEs HSDPA Capability
Classes
new UEs HSDPA Capability
Classes
Network Modifications for HSDPA
UTRAN & UE:• modified PHY layer• modified MAC
• modified transport and physical channels• modified coding• modified modulation
new Node B functionalities:• Acknowledged transmission: Fast H-ARQ faster retransmission / reduced delays ! less Iub retransmission traffic ! higher spectrum efficiency !
• Fast Packet Scheduling fast & efficient resource allocation !
• Fast Link Adaptation Adaptive Modulation & Coding ! compensation of fast fading (without fast PC) higher peak rates & spectrum efficiency !
Node B
10 © Nokia Siemens Networks RN31679EN30GLA1
TNL
MAC-d
DCHFP
DCHFP
MAC-d
TNL
Node B Iub RNC
RLC RLC
PHY PHY TNL
MAC-d
MAC-hsMAC-ehs
HS-DSCH FP
MAC-d
TNL
UE Uu Node B Iub RNC
RLC RLCMAC-d flow
HS-DSCH
PHY PHY
UE Uu
DCH
DPCH
HS-PDSCH
R99
HSDPA(R5)
(e)hs: (enhanced) high speedTNL : Transport Network Layer
HSDPA Protocol Model
MAC-hsMAC-ehs
HS-DSCH FP
HSDPA(R7)
11 © Nokia Siemens Networks RN31679EN30GLA1
MAC-hs• supports HSDPA with 3GPP Rel. 5 • Tasks of MAC-hs within the Node B
• Flow control • Packet scheduling• H-ARQ • Transport format selection
• Tasks of MAC-hs within the UE• HARQ (see section layer 1 re-transmission)• Disassembly of transport blocks• Re-ordering
• Header & payload • Payload: Concatenating of one or more MAC-d PDU into single MAC-hs PDU• Header: 21 bits assuming single MAC-d PDU size
MAC-ehs• supports enhanced HS-DSCH functions of 3GPP Rel. 7 - 9• must be configured to support features such as: 64QAM (RAN1643), MIMO (RAN 1642), flexible RLC (RAN1638),
Dual-Cell HSDPA (RAN1906)
MAC-hs & MAC-ehs
12 © Nokia Siemens Networks RN31679EN30GLA1
Physical Channel Overview : Transport Channel HS share channel
HS-PDSCHHigh-Speed Physical DL Shared Channel
HS-PDSCHHigh-Speed Physical DL Shared Channel
HS-SCCHHigh Speed Shared Control Channel
HS-SCCHHigh Speed Shared Control Channel
associated DCHDedicated Channel (Rel. 99)
associated DCHDedicated Channel (Rel. 99)
HS-DPCCHHigh Speed Dedicated Physical Control Channel
HS-DPCCHHigh Speed Dedicated Physical Control Channel
Node B
MAC-hs
F-DPCHFractional Dedicated Physical Channel (Rel. 6/7)
F-DPCHFractional Dedicated Physical Channel (Rel. 6/7)
13 © Nokia Siemens Networks RN31679EN30GLA1
HS-PDSCH (DL)• HS-PDSCH: High-Speed Physical Downlink Shared Channel
• Transfer of actual HSDPA data• 5 - 15 code channels• QPSK or 16QAM modulation• Divided into 2 ms TTIs• Fixed SF16
••• up to 15 HS – PDSCHs
HSPDSCHCodeSet HS-PDSCH code set; WCEL; (-) (-) (5 codes)
• HS-PDSCH code set parameter• Specifies whether number of
codes channels reserved for HSDPA is fixed* or dynamically
adjustable
• Minimum 5 code channels / Maximum 15 codes channels
• Possible numbers of code channels enabled / disabled bit wise
14 © Nokia Siemens Networks RN31679EN30GLA1
HS-SCCH (1/2)(DL)• HS-SCCH: High-Speed Shared Control Channel
• L1 Control Data for UE; informs the UE how to decode the next HS-PDSCH frame e.g. UE Identity, Channelization Code Set, Modulation Scheme, TBS, H-ARQ process
information• Fixed SF128• transmitted 2 slots in advance to HS-PDSCHs• NSN implementation with slow power control: shares DL power with the HS-PDSCH• more than 1 HS-SCCH required when code multiplexing is used
TBS: Transport Block Size
• Code multiplexing• HSDPA service for several users
simultaneously• For each user individual HS-
SCCH required• available only, if > 5 codes can
be reserved for HS-PDSCH
SF16HS-PDSCH
Time
User 1 User 2 User 3 User 4
Subframe2 ms
5
10
15
MaxNbrOfHSSCCHCodesMaximum number of HS-SCCH codes WCEL; RU10 & earlier: 1..3; 1; 1; RU20: 1..4
15 © Nokia Siemens Networks RN31679EN30GLA1
HS-SCCH (2/2)
128 128128
Available CCAllocated CC Blocked CC
SF16
SF32 32
SF64 64 64 64
SF256 256 256 256 256 256 256 256 256 256 256256 256256 256 256
128 128 128 128 128 128 128SF128
+15 x SF16
HS-PDSCH
CPICH
S-CCPCH1
S-CCPCH2 HS-SCCH HS-SCCH HS-SCCH
FACH-s: for Service Area Broadcast (CTCH)
P-CCPCHAICH
PICH
16 © Nokia Siemens Networks RN31679EN30GLA1
HS-DPCCH UL
• UL HS-DPCCH: High-Speed Dedicated Physical Control Channel• MAC-hs Ack/Nack information (send when data received)• Channel Quality Information (CQI reports send every 4ms, hardcoded period)• Fixed SF 256
HARQ-ACK(10 bit)
1 Slot = 2560 chip 2 Slots = 5120 chip
Subframe # 0 Subframe # i Subframe # N
1 HS-DPCCH Subframe = 2ms
CQI (20 bit)Channel Quality Indication
TS 25.21: CQI values = 0 (N/A), 1 .. 30; steps: 1;1 indicating lowest, 30 highest air interface quality
TS 25.21: CQI values = 0 (N/A), 1 .. 30; steps: 1;1 indicating lowest, 30 highest air interface quality
17 © Nokia Siemens Networks RN31679EN30GLA1
Associated DCH (DL & UL)
• DL DPCH: Associated Dedicated Physical Channel TPC• L3 signalling messages• Speech - AMR• Power control commands for associated UL DPCH
• UL DPCH: (DPDCH & DPCCH)• L3 signalling messages• Transfer of UL data 16 / 64 / 128 / 384 kbps, e.g. TCP
acknowledgements• Speech - AMR
DPDCH / DPCCH (time multiplexed)DPDCH: L3 signalling; AMR
DPCCH: TPC for UL DPCH power control
DPDCH: L3 signalling, AMR; TCP ACKs; 16 / 64 / 128 / 348 kbps
DPCCH: TPC, Pilot, TFCI
18 © Nokia Siemens Networks RN31679EN30GLA1
Fractional DPCH: F-DPCH (DL)
The Fractional DPCH (F-DPCH):• introduced in 3GPP Rel. 6 (enhanced in Rel. 7; NSN RU20 implementation based on
Rel. 7)• replaces the DL DPCCH• includes Transmit Power Control (TPC) bits but excludes TFCI & Pilot bits & SRB
– TFCI bits - no longer required as there is no DPDCH– Pilot bits - no longer required as TPC bits are used for SIR measurements– SRB mapped to E-DCH & HS-DSCH
• increases efficiency by allowing up to 10 UE to share the same DL SF256 channelization code
- time multiplexed one after another• RU20 feature RAN1201;
– requires Rel. 7 or newer UE– HSDPA & HSUPA must be enabled– Feature is licensed using an RNC ON/OFF license– License CPC exists and its state is ON
Tx OffTPC
Slot #i
1 time slot 2560 chips
Tx Off
256 chips
FDPCHEnabledWCEL; 0 (Disabled), 1 (Enabled)
19 © Nokia Siemens Networks RN31679EN30GLA1
SummaryCharacteristic RU10 RU20 RU30 RU40
HSDPA users per cell
≤ 64 ≤ 72 (RAN1668) ≤ 72 ≤ 128 (RAN2124)
Modulation QPSK/16QAMQPSK/16QAM & 64QAM (RAN1643)
QPSK/16QAM/64QAM QPSK/16QAM/64QAM
MIMO No Yes (2x2) (RAN1642) Yes Yes
Dual-Cell HSDPA No Yes (RAN1906) DC-HSDPADC-HSDPADB DC HSDPA (RAN2179)
Data rate per UE up to 14 Mbps up to 42 Mbpsup to 42 Mbps 84 Mbps (RAN 1907)
up to 84 Mbps (RAN1907)
Traffic ClassesInteractive + Background + Streaming
+ CS Voice over HSPA (RAN1689)
all traffic classesall traffic classes
Packet SchedulerProportional Fair (PF)+ QoS Aware HSPA Scheduling
PF + QoS aware scheduling
PF + QoS awarescheduling
PF + QoS awarescheduling
HSDPA Multi-RAB multiple RAB HSDPA + AMR
multiple RAB HSDPA + AMR
multiple RAB HSDPA + AMR, +CS64 Conv.
multiple RAB HSDPA + AMR, +CS64 Conv.
Code Multiplexing(Scheduled users per TTI)
Yes (up to 3) Yes (up to 4) Yes (up to 4) Yes (up to 4)
UL associated DCH 16, 64, 128, 384 Kbps 16, 64, 128, 384 Kbps 16, 64, 128, 384 Kbps 16, 64, 128, 384 Kbps
DB: Dual Band
20 © Nokia Siemens Networks RN31679EN30GLA1
•Most enhanced features must be licensed individually and are activated by setting individual off / on parameter
•Some features can be activated on cell level, others on WBTS or even RNC level only
Feature Activation
HSDPAenabledWCEL; 0 = disabled; 1 = enabled
HSDPA48UsersEnabledRNFC; 0 = disabled; 1 = enabled
HSDPA64UsersEnabledWCEL; 0 = disabled; 1 = enabled
HSDPA14MbpsPerUserWBTS; 0 = disabled; 1 = enabled
HSDPAMobilityServing HS-DSCH cell change & SHO on/off switchRNFC ; 0 = disabled; 1 = enabled
HspaMultiNrtRabSupportHSPA multi RAB NRT supportWCEL; 0 = disabled; 1 = enabled
HSDPADynamicResourceAllocationHSDPA Dynamic Resource AllocationRNFC; 0 = disabled; 1 = enabled
HSDPA16KPBSReturnChannelHSDPA 16 Kbps UL DCH return channel on/offRNFC; 0 = disabled; 1 = enabled
HSPA72UsersPerCellWCEL; 0 = disabled; 1 = enabledif enabled, max. 72 HSDPA/HSUPA users can be supported per cell.
HSPA128UsersPerCellWCEL; 0 = disabled; 1 = enabledif enabled, max. 128 HSDPA/HSUPA users can be supported per cell.
RU20/30
HSDPA64QAMAllowed; MIMOEnabled; DCellHSDPAEnabled; MIMOWith64QAMUsageWCEL; 0 (Disabled), 1 (Enabled)
DCellAndMIMOUsageWCEL; 0=DC-HSDPA and MIMO disabled; 1=DC-HSDPA and MIMO w/o 64QAM enabled; 2=DC-HSDPA and MIMO with 64QAM enabled
FDPCHEnabled; CPCEnabledWCEL; 0 (Disabled), 1 (Enabled)
HSPAQoSEnabledWCEL; 0..4; 1; 0 = disabled0 = QoS prioritization is not in use for HS transport1 = QoS prioritization is used for HS NRT channels2 = HSPA streaming is in use3 = HSPA CS voice is in use4 = HSPA streaming & CS voice are in use
RU40
21 © Nokia Siemens Networks RN31679EN30GLA1
HSDPA RRM
22 © Nokia Siemens Networks RN31679EN30GLA1
Link adaptation algorithm1) Generation of CQImeasured :
– UE monitors EC/I0
– UE reads PHS-PDSCH SIG (L3/RRC signalling)
2) UE reports CQImeasured every 4 ms (NSN solution) – can be increased with Mass Event Eandler
3) CQI Correction in Node BNode B corrects reported CQImeasured to CQIcompensated based on:
– actual HS-PDSCH power PHS-PDSCH TRUE
– Number of ACK & NACK
4) Link Adaptation decision: Node B decides about TB size for next sub-frame:– Modulation– Coding rate– Number of codes
CQI Reporting & Link Adaptation
••• up to 15 HS – PDSCHs
P-CPICH
HS – DPCCH (ACK; CQI)HS – SCCH
CQI used for:• Link Adaptation decision • Packet Scheduling decision
ACK/NACK used for:• H-ARQ process • Link Adaptation decision • HS-SCCH power adaptation
Remember:
* UE internal (proprietary) process
PHS-PDSCH: HS-PDSCH transmission power
TB: Transport Block
UE observesP-CPICH (Ec/Io)
CQImeasured*
CQImeasured*
23 © Nokia Siemens Networks RN31679EN30GLA1
CQI Compensation (1/3)CQImeasured
UE generates CQImeasured assuming Tx power PHS-PDSCH SIG = PCPICH + +
– calculated by RNC: = f x Min(PtxMaxHSDPA, PtxMax – PtxNonHSDPA) – PCPICH
PHS-PDSCH SIG = (f x Min(PtxMaxHSDPA, Ptxmax – PtxNonHSDPA)) [dBm] +
= Reference Power Adjustment (Power Offset) [dB] CQI tablesPtxMax = max. cell powerPtxNonHSDPA = total power allocated to R99 & DL control channels (latest report is taken)PtxMaxHSDPA = max. allowed HSDPA power
signalled to UE in case of HS-DSCH setup
Serving cell change
f = 0.7 for static HS-PDSCH power allocationf = 0.5 for dynamic HS-PDSCH power
CQI Compensation in Node B• Node B compensates CQI from differences between assumed HS-PDSCH
Tx power & actual HS-PDSCH Tx power PHS-PDSCH TRUE
– Part of HSDPA power used for HS-SCCH– HS-PDSCH power can vary because of dynamic power allocation
• Offset X used to convert reported CQImeasured into compensated CQIcompensatedCQIcompensated = CQImeasured + X [dB]
X = PHS-PDSCH TRUE – (PCPICH + + ) – A [dB]
correction A estimated by outer loop link adaptation algorithm
24 © Nokia Siemens Networks RN31679EN30GLA1
Outer loop link adaptation algorithm correction A• If ACK received for first transmission of a packet
– Correction A decreased by 0.005 dB– But not below -4 dB (maximum CQI improvement towards higher TBS)
• If NACK received for first transmission of a packet– Correction A increased by 0.05 dB– But not above 4 dB (maximum CQI downgrade towards lower TBS)
ACK for 1st transmission
NACK for 1st transmission
time
P0
CQI Compensation (2/3)
increase CQI
lower CQI
25 © Nokia Siemens Networks RN31679EN30GLA1
CQIMEASURED = 3233 bits per TB (167 K)e.g. PHS-PDSCH SIG = 37 dBm
e.g. PHS-PDSCH TRUE = 40 dBmX = (40 – 37) dB = 3 dBCQICOMPENSATED = 3 + 3 = 6461 bits per TB (230 K)
X = 3 dB
• CQI compensation makes it difficult to map reported CQI from UE log files into expected HSDPA transport block size TBS
CQI Compensation (3/3)
26 © Nokia Siemens Networks RN31679EN30GLA1
0
5
10
15
20
25
30
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5
CPICH Ec/Io (dB)
Com
pens
ated
Cha
nnel
Qua
lity
Indi
cato
r (C
QI)
PtxMaxHSDPA = 30 dBm
PtxMaxHSDPA = 35 dBm
PtxMaxHSDPA = 40 dBm
Compensated
Reported
CQI as a function of CPICH Ec/Io
Measurement Examples
• CQI improves both with increasing:
– EC/I0
– HSDPA power
27 © Nokia Siemens Networks RN31679EN30GLA1
• CQI estimation differs from one type of UE to the next one Prediction of different values in spite of identical channel conditions• CQI compensation capable to remove most of these differences Almost same service experienced in spite of proprietary CQI estimation
0
5
10
15
20
25
30
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3
CPICH Ec/Io (dB)
Cha
nnel
Qua
lity
Indi
cato
r (C
QI)
Samsung zx20
Novatel U740
Common Channel Loaded
Unloaded
0
5
10
15
20
25
30
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3
CPICH Ec/Io (dB)
Com
pens
ated
Cha
nnel
Qua
lity
Indi
cato
r (C
QI) Samsung zx20
Novatel U740
Common Channel Loaded
Unloaded
Prior to compensation After compensation
Measurement Examples
28 © Nokia Siemens Networks RN31679EN30GLA1
HSDPA RRM
29 © Nokia Siemens Networks RN31679EN30GLA1
R99 & HSDPA Retransmission
Terminal
BTS
R99 DCH R5 HS-DSCH
Packet
Re-transmission
RLC ACK/NACK
Re-transmission
L1 ACK/NACK
Packet
Terminal
BTS
RNC RNC
Dat
aflo
w
DL control moved to BTS
H-ARQ: Hybrid Automatic Repeat reQuest
30 © Nokia Siemens Networks RN31679EN30GLA1
Hybrid Automatic Repeat Request H-ARQ
• H-ARQ Objective:– ensures reliable data transfer between UE and Node B– short Round Trip Time between UE and network
• HSDPA connection re-transmission can originate from:– MAC-hs layer between UE and Node B (HARQ)– RLC layer between UE and RNC– TCP layer between UE and application server
• Re-transmission time out– after 3rd L1 re-transmission HSDPA packet discarded (hardcoded threshold)
• HARQ algorithms:– Chase combining CC– Incremental Redundancy IRAlgorithm selected by operator on BTS level
HARQRVConfigurationWBTS; 0 = Chase
Combining, 1 = Incremental
Redundancy
31 © Nokia Siemens Networks RN31679EN30GLA1
HSDPA RRM
32 © Nokia Siemens Networks RN31679EN30GLA1
Scheduler Types
• Supports packet schedulers– Round Robin RR
– Proportional Fair PF (requires individual license)
– Type of scheduler set by HSDPA.BB.Resource.Allocation commissioning parameter
Round Robin Scheduler• assigns sub-frames in rotation
– User at cell edge served as frequently as user at cell centre
• does not account for channel conditions experienced by UE– Low total throughput in cell
• if no data have to be transferred from Node B to certain UE then the sub-frame is assigned to the next one
33 © Nokia Siemens Networks RN31679EN30GLA1
Proportional Fair PF Scheduler (1/2)
TTI 1 TTI 2 TTI 3 TTI 4
USER 1 Es/N0USER 2 Es/N0
Scheduled user
• Takes into account multipath fading conditions experienced by UE
– Improved total throughput in cell in comparison to round robin
• Sub-frames assigned according scheduling metric
– Ratio instantaneous data rate / average data rate experienced in the past
– User at cell edge served less frequently as user at cell centre
Estimate of instantaneously supported user throughput
Based on compensated CQI
Calculated average user throughput in the past
Throughput measured every 10 ms with 100 ms sliding window
ave
inst
TP
TP
34 © Nokia Siemens Networks RN31679EN30GLA1
Round Robin RR scheduling
Max. total throughput 1100 KbpsProportional Fair PF scheduling
Max. total throughput 1300 Kbps
Example:
Macro cell≤ 5 codes for HSDPACarrier shared with R99Maximum total transmission power 20
WStatic HS-PDSCH + HS-SCCH power
Proportional Fair PF Scheduler (2/2)
35 © Nokia Siemens Networks RN31679EN30GLA1
Scheduling / HSDPA Code Multiplexing
UE1 UE2 UE3
Amount of
data in buffer
UE1 UE2 UE3
Full buffer Different data amounts
7
8
7
8
RU10 & later
15 codes2
10
5
8
3
10
Codes & power are divided optimally between users depending on data amount.
MaxNbrOfHSSCCHCodes
Max. number of HS-SCCH codesWCEL; 1..4*; 1; 1
(no Code Multiplexing)
HSDPA Code Multiplexing: enables simultaneous transmission of up to 4* HSDPA UEs during 1 TTI
– each simultan. served HSDPA UEs must have separate HS-SCCH– ≥ 5 codes must be allocated to HS-PDSCH– MAC-hs entity selects (3) best users (based on PF or QoS aware metric) for transmission in the next TTI– HS-PDSCH codes & power resources shared, taking into account:
how much data user has in its buffer Channel conditions of user
* 3 before RU20
36 © Nokia Siemens Networks RN31679EN30GLA1
Basics of QoS Aware Scheduling• Shortcomings of standard PF
– PF metric does not distinguish between traffic classes– No bit rate guarantee, i.e. no streaming services supported– Interactive service not prioritised against background one
• Idea of QoS aware HSPA scheduling (RAN1262)– QoS aware HSPA scheduling enabled with parameter HSPAQoSEnabled– HSDPA dynamic resource allocation must be enabled– Streaming services
Guaranteed bit rate set by RNC– Interactive IA & Background BG services
Operator can set nominal bit rate (target minimum bit rate)If not defined, service treated as best effort one
Operator can set service priorities, so that IA services are scheduled more often than BG onesServices belonging to same traffic class againscheduled according PF
HSPAQoSEnabledWCEL; 0..4;1; 0 = disabled0 = QoS prioritization is not in use for HS transport1 = QoS prioritization is used for HS NRT channels2 = HSPA streaming is in use (RAN1004)3 = HSPA CS voice is in use (RAN1689)4 = HSPA streaming and CS voice are in use
38 © Nokia Siemens Networks RN31679EN30GLA1
Application Aware RAN – NSN implementation
Application Aware RAN solution is implemented in 2 network elements GGSN and RNC
1. In GGSN: Core network based DPI (Deep Packet Inspection) provides application detection and inner (user) IP packet marking with DSCP (Differential Service Code Point - a field in the IPv4 and IPv6 header)
DSCP of user packet is marked based on PCC rule action
2. In RNC: Initial Scheduling Priority Indicator of the radio bearer is demoted or promoted in the RNC PDCP layer according to Deep Packet Inspection marking (DSCP marking).
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Overview HS-PDSCHHigh-Speed Physical DL Shared Channel
HS-PDSCHHigh-Speed Physical DL Shared Channel
HS-SCCHShared Control Channel for HS-DSCH
HS-SCCHShared Control Channel for HS-DSCH
associated DCH*Dedicated Channel
associated DCH*Dedicated Channel
HS-DPCCHDedicated Physical Control Channel (UL) for HS-DSCH
HS-DPCCHDedicated Physical Control Channel (UL) for HS-DSCH
Static power allocationTx power „fixed“Slowly adjusted in dependence on HS-SCCH Tx power
Dynamic power allocationAll power not needed for R99 services available for HSDPASlowly adjusted in dependence on R99 & HSDPA traffic
Fast power control in dependence on:- CQI- Feedback of UE
Fast power control parallel to DPCCH with offset for CQIACK/NACK
Inner loop PC basing DL TPC and CQI
WBTSUE
F-DPCH*Fractional Dedicated Physical Channel
F-DPCH*Fractional Dedicated Physical Channel
* F-DPCH can be allocated in DL only if SRB can be mapped to HSPA channels
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HS-PDSCH Power Allocation
Static Power Allocation Dynamic Power Allocation
• PHSDPA ≤ PtxMaxHSDPA PHSDPA ≤ min(PtxMaxHSDPA, PtxCellMax)-
power allocated to R99 DCH & DL control channels• Fixed load target PtxTargetHSDPA Dynamically adjusted load target PtxTargetPS• Fixed overload threshold for R99 Overload threshold for R99 goes parallel to
load target:PtxTargetHSDPA + PtxOffsetHSDPA PtxTargetPS + PtxOffset
• In case of overload HSDPA might be In case of overload HSDPA power might be reduced,released immediately but usually service not released immediately
• Priorities distinguish between R99 & Priorities distinguish between interactive & background
• HSDPA users only users as well
PtxMaxHSDPAMaximum allowed HSDPA powerWCEL; 0..50 dBm; 0.1 dB; 43 dBm
PtxTargetHSDPA Target for transmitted non-HSDPA
powerWCEL; -10..50 dBm; 0.1 dB; 38.5 dBm
PtxOffsetHSDPAOffset for transmitted non-HSDPA powerWCEL; 0..6 dB; = 0.1 dB; 0.8 dB
HSDPADynamicResourceAllocationHSDPA Dynamic Resource Allocation RNFC; 0 = disabled; 1 = enabled
PtxCellMaxCell maximum transmission powerWCEL; 0 .. 50 dBm; 0.1 dB; 43 dBm
PtxOffsetOffset for transmitted powerWCEL; 0 .. 6 dB; 0.1 dB; 1 dB
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• BTS may allocate all unused DL power up to maximum cell power• all power available after DCH traffic, HSUPA control & common channels can be used for
HSDPA
PtxNC
PtxNRT
PtxHSDPA
PtxMax = min (PtxCellMax, MaxDLPowerCapability)
PtxNonHSDPA
Dynamic HS-PDSCH Power Allocation (1/7)
PtxCellMaxCell maximum transmission power0..50 dBm; 0.1 dB; 43 dBm
MaxDLPowerCapability: 0..50 dBm; 0.1 dB; -
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Dynamic HS-PDSCH Power Allocation (2/7)
No active HSDPA users• NRT DCH scheduling to
– PtxTarget + PtxOffset if HS-RACH isn’t set up in the cell
– PtxTargetPS if HS-RACH is set up in the cell
• RT DCH admission to PtxTarget
Active HSDPA users• NRT DCH scheduling to
PtxTargetPS • RT DCH admission to
– PtxTarget no RT HS-SDCH– PtxTargetTot at least 1 RT HS-DSCH
HSDPA activeNo HSDPA users No HSDPA users
PtxTarget + PtxOffset
PtxMax
PtxTargetPS
PtxNC
PtxNRT
PtxHSDPA
1
2
3
PtxNonHSDPA
PtxTotal
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Dynamic HS-PDSCH Power Allocation (3/7)• Adjustable load target PtxTargetPS
– PtxTargetPSMin (minimum value)– PtxTargetPSMax (maximum value, also initial value, HS-RACH is set up in the cell)– PtxTargetPSMaxHSRACH (maximum value used if HS-RACH is set up in the cell)
PtxTargetPSMinMin DCH PS target for dynamic HSDPA pwr allocationWCEL; -10..50 dBm; 0.1 dB; 36 dBm
PtxTargetPSMaxMax DCH PS target for dynamic HSDPA pwr allocationWCEL; -10..50 dBm; 0.1 dB; 40 dBm
PtxTargetPSMaxHSRACHMax DCH target power level with HS-RACH for dynamic HSDPA pwr allocationWCEL; 0..40 dBm; 0.1 dB; 32767 dBm (Value set by the PtxTargetPSMax parameter used when the HS-RACH has been setup in the cell)
PtxNC
PtxNRT
PtxHSDPA
PtxMax
PtxNonHSDPA
PtxTargetPSMin (36 dBm)
PtxTargetPSMax (40 dBm)PtxTargetPS
PtxTargetPSMin-10..50 dBm; 0.1 dB; 36 dBm
PtxTargetPSMax-10..50 dBm; 0.1 dB; 40 dBm
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Load Target Adjustment (6/7)
• Required information– Total power PtxTotal measured by Node B– Non HSDPA power PtxNonHSDPA measured by Node B– Both averaged according PSAveragingWindowSize (same parameter as for R99)
• Need for adjustment checked periodically according PtxTargetPSAdjustPeriod• If adjustment needed
– Increase by PtxTargetPSStepUp in case of DCH congestion– Decrease by PtxTargetPSStepDown in case of HSDPA congestion
PSAveragingWindowSize Load measurement averaging window size for PS WBTS; 1..20; 1; 4 scheduling periods
PtxTargetPSAdjustPeriodDCH PS target adjust period for dyn HSDPA power alloc; WBTS; 1..255; 1; 5 RRI periods
PtxTargetPSStepUpDCH PS target step up for dynamic HSDPA pwr alloc.WCEL; 0..5; 0.1; 1 dB
PtxTargetPSStepDownDCH PS target step down for dynamic HSDPA pwr alloc.WCEL (0..5 dB) ( = 0.1 dB) (1 dB)
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Actions in Case of Congestion (7/7)
DCH congestion only• Increase PtxTargetPS by PtxTargetPSStepUp, if currently below ideal load target (but not above PtxTargetPSMax)
HSDPA congestion only• Decrease PtxTargetPS by PtxTargetPSStepDown, if currently above ideal load target (but not below PtxTargetPSMin)
Both DCH & HSDPA congestion• Increase PtxTargetPS, if currently below ideal load target• Decrease PtxTargetPS, if currently above ideal load target
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Static & Dynamic Allocation (1/3)
HSPDSCHCodeSet11010 10100
100000
HSPDSCHCodeSet00000 10100
100000
HSPDSCHCodeSet00000 00000 100000
Additionally required HSDPADynamicResourceAllocation =
enabled
Number of HS-
PDSCH codes (full
set)
HSDPA
15
Codes
HSDPA
10
Codes
Static
code
allocation
5 X X X
6 - - -
7 - - -
8 X X -
9 - - -
10 X X -
11 - - -
12 X - -
13 - - -
14 X - -
15 X - -
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Static & Dynamic Allocation (2/3)
Dynamic code allocation applied if:• HSDPA dynamic resource allocation
enabled (HSDPADynamicResourceAllocation)
• Maximum number of codes > minimum number (HSPDSCHCodeSet)
• BTS capable of 10/15 codes• HSDPA service starts with minimum
number of codes defined by HSPDSCHCodeSet
• Cell-specific scheduler reserves HS-SCCH codes from the spreading code tree according to MaxNbrOfHSSCCHCodes
If HSDPA dynamic resource allocation disabled, 5 codes are available only
SF=8
SF=4
SF=2
SF=1
SF=161514131211109876543210
HS-PDSCH
………. ……….
SF=8
SF=4
SF=2
SF=1
SF=161514131211109876543210
HS-PDSCHRel-99 channels(& HS-SCCH)
Rel-99 code area (& HS-SCCH)
Shared code area
Dedicated HS-PDSCH
SF=8
SF=4
SF=2
SF=1
SF=161514131211109876543210
HS-PDSCH
………. ……….
SF=8
SF=4
SF=2
SF=1
SF=161514131211109876543210
HS-PDSCHRel-99 channels(& HS-SCCH)
Rel-99 code area (& HS-SCCH)
Shared code area
Dedicated HS-PDSCH code area
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Static & Dynamic Allocation (3/3)
128 128128
Available CCAllocated CC Blocked CC
SF16
SF32 32
SF64 64 64 64
SF256 256 256 256 256 256 256 256 256 256 256256 256256 256 256
128 128 128 128 128 128 128SF128
+14 x SF16
HS-PDSCH
CPICH AICH
S-CCPCH1
S-CCPCH2HS-SCCH HS-SCCH HS-SCCH
32
64 64
256 256 256 256 256 256 256 256
128 128 128 128
SF16
E-RGCH E-HICH
E-AGCH
Maximum of 14 HS-PDSCH codes possible with 3 HS-SCCH & HSUPA
P-CCPCH PICH
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Dynamic Allocation Procedure (1/2)
Periodic upgrade• HSDPA service starts with minimum number of codes• RNC attempts periodic upgrade according the timer
HSPDSCHAdjustPeriod if• Number of currently allocated HS-PDSCH codes < maximum allowed
number supported by BTS capability• Free SF 16 codes adjacent to currently allocated ones available• After upgrade enough SF 128 codes available according
HSPDSCHMarginSF128• If all conditions are fulfilled, the next greater value from HS-PDSCH code
set is taken
Periodic downgrade• RNC attempts periodic downgrade according the timer
HSPDSCHAdjustPeriod if• Number of currently allocated HS-PDSCH codes > minimum allowed
number• Not enough SF 128 codes available according HSPDSCHMarginSF128
• If all condition fulfilled, the next lower value from HS-PDSCH code set is taken
HSPDSCHMarginSF128
WCEL; 0..128; 1; 8# SF128 codes to be available after Code
upgrade
HSPDSCHAdjustPeriodRNHSPA; 1..60; 1; 10s
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Dynamic Allocation Procedure (2/2)N
um
be
r o
f a
llo
ca
ted
SF
16
co
de
s
DPCHOverHSPDSCHThresholdset relative to max. number of codes
6789101112131415 Maximum code
set
5
• Code congestion events– RT request congested due to lack of code HS-PDSCH downgrade in any case– NRT request congested due to lack of code HS-PDSCH downgrade only, if actually for HSDPA
too much SF 16 codes in use according DPCHOverHSPDSCHThreshold
• Limitations of congestion triggered downgrade– Not below minimum allowed number of HS-PDSCH codes– Highest still possible number of codes according HSPDSCHCodeSet is taken
Minimum code set
HSPDSCHCodeSet
WCEL; 5..15; 1; 5
DPCHOverHSPDSCHThreshold
WCEL; 0..10; 1; 5
Code tree optimization• Code tree optimization procedure tries to re-arrange DPCH
codes to make room for HS-PDSCH code upgrade• DPCHs having SRB DCH only are not allowed to be re-arranged
CodeTreeOptimisationWCEL; 0 = disabled; 1 = enabled
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HSPDSCHCodeSet
WCEL; 5..15; 1; 5
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DPCHOverHSPDSCHThreshold
WCEL; 0..10; 1; 5
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HSDPA Mobility
Serving Cell Change SCC (1/5): CandidateInitial cell selection• 1 cell active only: just attempt to establish service
• More than 1 cell active– Initial selection of Serving Cell based on latest reported Ec/I0
– To be candidate, HSDPA capable cell must fulfil following condition:
– Serving cell is chosen in order of EC/I0
– If allocation of HS-DSCH fails due to any reason, next best candidate cell is attempted
EC/I0 (active cell*) ≥ EC/I0 (best cell) – HSDPAServCellWindow
HSDPAServCellWindowCPICH Ec/Io window for serving HS-
DSCH cell selectionRNMOBI; 0..6; 0.5; 2 dB
* Serving Cell
Max. allowed difference between the best cell in the Active Set & the Serving HSDSCH cell. If Serving HS-DSCH cell out of this window Serving HS-DSCH cell change procedure initiated.
Methods to handle HSDPA mobility• Serving HS-DSCH cell change• Cell reselection with HS-DSCH - FACH channel type switching
HSDPAMobilityServing HS-DSCH cell change & SHO on/off
switchRNFC; 0 = HSDPA cell reselection 1 = Serving HS-DSCH cell change
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Directed RRC Connection Setup
Enhanced functionality• More than 2 layers supported• Can be restricted to certain types of
services• Load balancing applied• R99 directed RRC connection setup
simultaneously supported• Layering in Cell_FACH supported
(same rules as for RRC con. setup)
HSDPALayeringCommonChEnabled HSDPA layering for UEs in common channels enabled
WCEL; 0 = disabled; 1 = enabled
Basic functionality• Only for 2 layers• Service (cause for RRC connection
setup) not considered• Load of target layer not
considered• Cannot be used simultaneously
with
R99 directed RRC connection setup
• Layering in Cell_FACH supported
(same rules as for RRC con. setup)
Basic feature• Target
– R5 or newer UEs directed from non-HSDPA supporting carrier to HSDPA supporting one
– R99 or R4 UEs directed from HSDPA supporting carrier to non-HSDPA supporting one
– Feature works within same sector defined by SectorID
• Required parameter settings– DirectedRRCForHSDPALayerEnabled =
enabled– DirectedRRCForHSDPALayerEnhanc =
disabled
DirectedRRCForHSDPALayerEnabled
WCEL; 0 = disabled; 1 = enabled
DirectedRRCForHSDPALayerEnhancRNMOBI; 0 = disabled; 1 =
enabled
SectorIDWCEL; 0..12; 1; 0 = cell not
belonging to any sector
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Enhanced feature• Non-HSDPA UEs
– Directed away from HSDPA capable cell if Load of the target cell not too big (i.e. R99 load balancing
back to source cell not triggered)
• HSDPA UEs– Directed away from non-HSDPA capable cell if
Establishment cause indicated by UE allowed in HSDPA layer Not too much HS-DSCH users in target cell
– Directed to other HSDPA capable cell if Load balancing required Establishment cause indicated by UE allowed in HSDPA layer
• HSUPA UEs– Same rules as for HSDPA UEs, but additionally
Directed to HSUPA capable cell if possible Not directed away from HSUPA capable cell
Directed RRC Connection Setup