04_Capacity_management.pdf
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3G RANOP RU20 Module Module 4 – Capacit Capacity y Ma Manag nagemen ementt
Confidential 1 © Nokia Siemens Networks
Presentation / Author / Date
Course Content KPI overview Performance monitoring Air interface and neighbor optimization Capacity management Paging and inter-RNC optimization
Confidential 2 © Nokia Siemens Networks
Presentation / Author / Date
Module Objectives
At the end of the module you will be able to: Describe 3G RAN traffic, load, blocking due to different scenarios Describe 3G monitoring and potentials of capacity enhancement load features Describe 3G/HSPA counters & KPI’s to improve capacity by less blocking
Confidential 3 © Nokia Siemens Networks
Capacity optimization Principles of capacity monitoring - Capa Capacity city bott bottlene lenecks cks - Reactive Reactive / proactiv proactive e monitoring monitoring - RU RU20 20 Impro Improvem vement ents s
Monitoring of R99 blocking - Air inter interfac face e TCP / RTWP RTWP - Chan Channel nel Cards Cards / Code Tree, Tree, - UTRAN interface interfaces s Iub / Iur Iur - Features Features to reduce reduce blocking blocking
Monitoring of HSPA congestion and blocking - Bott Bottle lene neck cks s - HSDPA HSDPA power power consump consumption tion / CQI - Dynami Dynamic c HSDPA HSDPA powe power r - Chan Channel nel Cards Cards / Code Tree - User User Equipm Equipment ent
Confidential 4 © Nokia Siemens Networks
Capacity bottlenecks RNC
WBTS
UE
IuCS Interface User Plane User Plane
AIR Interface
WSP Resource
IuB Interface CNBAP
PRACH
Throughput Connectivity Unit Load
PCH
Code Capacity
WCDMA network interfaces and internal resources should be monitored
User Plane
DSP Usage
U s e r P l a n e
D-RNC
Confidential 5 © Nokia Siemens Networks
IuPS Interface
DNBAP
FACH-c&u
DCH
SS7 (RANAP)
User Plane SS7 (RANAP)
Iur Interface
Reactive / proactive monitoring KPIs • Daily BH analysis needed for Reactive monitoring • Weekly analysis enough for Proactive monitoring
W-BTS Iub Confidential 6 © Nokia Siemens Networks
RU20 improvement Capacity “Upgrade”
- -
RU 20 features Power Saving Mode for BTS new Fractional DPCH HSPA over Iur HSUPA 2ms TTI Flexible RLC (DL) HSDPA 64QAM Continuous Packet Connectivity (DTX for signaling DPCCH) HSPA 72 Users Per Cell CS Voice over HSPA* MIMO 2x2* DC-HSDPA 42Mbps* Dual carrier new HSUPA 5.8 Mbps 24 kbps Paging Channel (normal 8 kbps) Fast L1 Synchronization Interworking and Network Evolution LTE Interworking* HO to LTE
Confidential 7 © Nokia Siemens Networks
- -
value drivers - improvements less total interference within networks Fractional DPCH less signaling via Iu interface, less load within transmission HSUPA speed will increase less overhead (PDU) Higher spectral efficiency (Mbps/MHz) new less signaling load, more capacity more users can be managed DCH switched off, more speed more HSPA PwR High data and better antenna efficiency More speed, but second carrier activation UL high dedicated data More access capability Quicker access for service (RRC setup 70 ms improvement) 3G NW interact with LTE (Dual mode)
Capacity optimization Principles of capacity monitoring
OSS monitoring Performance department is more happy
Confidential 8 © Nokia Siemens Networks
Capacity optimization Principles of capacity monitoring - Capacity bottlenecks - Reactive / proactive monitoring - RU20 Improvements
Monitoring of R99 blocking - Air interface TCP / RTWP - Channel Cards / Code Tree, - UTRAN interfaces Iub / Iur - Features to reduce blocking
Monitoring of HSPA congestion and blocking - Bottlenecks - HSDPA power consumption / CQI - Dynamic HSDPA power - Channel Cards / Code Tree - User Equipment
Confidential 9 © Nokia Siemens Networks
Air interface TCP / RTWP blocking (1/3) • First – – evaluation of TCP / RTWP blocking • Then – – channel cards / code tree • Finally Iub/Iur interfaces and RNC
Power & interference management
• Too many RB assignments • Radio interface quality and coverage (Ec/Io, RSCP) • Neighbor cell interference • UE (terminal problem)
Confidential 10 © Nokia Siemens Networks
Air interface TCP / RTWP blocking (2/3) UL (RTWP)
Blocking due to congestion
Noise Rise [dB]
Overloaded Area Marginal Load Area
PrxTarget [dB] + PrxOffset [dB] Prx Tar et dB
Feasible Load Area
RB allocation by AC/PS
Confidential 11 © Nokia Siemens Networks
η) [0..1] load (η
Max load
Air interface TCP / RTWP blocking (3/3) DL (TCP)
Blocking due to congestion
total transmitted power [dBm]
Overloaded Area Mar inal Load Area
Ptx Target [dBm] + PtxOffset [dB] Ptx Target [dBm]
Feasible Load Area RB allocation by AC/PS
load (η η) Range Ptx Total [0… Ptx BS total] Confidential 12 © Nokia Siemens Networks
Max load
Channel card / code tree blocking (1/3) Example: Less CE usage with throughput based optimization AVE_CE_USED_AMR (Cellres)
Average CE Used
Avg CE used PS UL Avg CE used PS DL
6
r e r a e b / E C
5
4
2
1
0 7 0 0 2 / 7 / 9
7 0 0 2 / 8 / 9
7 0 0 2 / 9 / 9
7 0 0 2 / 0 1 /
7 0 0 2 / 1 1 /
7 0 0 2 / 2 1 /
7 0 0 2 / 3 1 /
7 0 0 2 / 4 1 /
7 0 0 2 / 5 1 /
7 0 0 2 / 6 1 /
7 0 0 2 / 7 1 /
7 0 0 2 / 8 1 /
7 0 0 2 / 9 1 /
7 0 0 2 / 0 2 /
7 0 0 2 / 1 2 /
7 0 0 2 / 2 2 /
7 0 0 2 / 3 2 /
9
9
9
9
9
9
9
9
9
9
9
9
9
9
Average CE used for AMR traffic kept in same level as before Average CE used for PS traffic reduced by 30 – 40% both on UL and DL Confidential 13 © Nokia Siemens Networks
AMR needs 1 CE PS 64/128 needs 4 Ces PS 32 kbps needs 2 CEs
Channel card / code tree blocking (2/3) Example: code tree blocking rate in dependence on SF Pink is SF8 blocking rate – SF8 blocking/SF8 requested
Blue line represent the whole code tree blocking rate
100
Yellow is SF16 blocking rate – SF16 blocking/SF16 requested
80
In this case, major part of blocking is coming from SF8 - Blocking can be relative high and still there can be enough capacity to set initial bitrate
60
40
20
0 1
4
7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91
-20 Code_Tree_Blocking_Rate
SF8_Blocking_rate
SF16_Blocking_rate
SF32_Blocking_rate
SF64_Blocking_rate
SF128_Blocking_rate
SF256_Blocking_rate
Confidential 14 © Nokia Siemens Networks
Channel card / code tree blocking (3/3) KPIs for code tree blocking (and HSDPA downgrade due to lack of codes)
PI
Name
Unit
Object
Formula
WCEL
(1-100*(sum( THE NBR OF SUCC CODE THREE ALLO)/sum( CHANNELIZATION CODE SF4 REQUESTED+ CHANNELIZATION CODE SF8 REQUESTED+ CHANNELIZATION CODE SF16 REQUESTED+ CHANNELIZATION CODE SF32 REQUESTED+ CHANNELIZATION CODE SF64 REQUESTED+ CHANNELIZATION CODE SF128 REQUESTED + CHANNELIZATION CODE SF256 REQUESTED)
RNC_949a
SF code blocking rate
RNC _ 512b
SF4 blockin rate
RNC_513b
SF8 blocking rate
%
WCEL
100%*(NO_CODES_AVAILABLE_SF8 / CHAN_CODE_SF8_REQUESTED)
RNC_514b
SF16 blocking rate
%
WCEL
100%*(NO_CODES_AVAILABLE_SF16 / CHAN_CODE_SF16_REQUESTED)
RNC_515b
SF32 blocking rate
%
WCEL
100%*(NO_CODES_AVAILABLE_SF32 / CHAN_CODE_SF32_REQUESTED
RNC_516b
SF64 blocking rate
%
WCEL
100%*(NO_CODES_AVAILABLE_SF64 / CHAN_CODE_SF64_REQUESTED)
RNC_517b
SF128 blocking rate
%
WCEL
100%*(NO_CODES_AVAILABLE_SF128 / CHAN_CODE_SF128_REQUESTED)
RNC_518b
SF256 blocking rate
%
WCEL
100%*(NO_CODES_AVAILABLE_SF256 / CHAN_CODE_SF256_REQUESTED)
M1000C266
HSDPA CH code downgrade due RT
#
WCEL
CH_CODE_DOWNG_RT
M1000C267
HSDPA CH code downgrade due NRT
#
WCEL
CH_CODE_DOWNG_NRT_DCH
Confidential 15 © Nokia Siemens Networks
%
*
_
_
_
_
_
_
Iub / Iur interface blocking (1/2) Example: Less reserved ATM cell rate with throughput based optimization • As the consequence of
1180000
lower PS RB allocation, Maximum Reserved AAL2 (cell rate) VCI 36 the maximum reserved cell rate in AAL2 has reduced considerably Sum of MAX_RESERVED_CE LL_RATE (Aal2cac)
1160000 1140000 1120000 1100000 1080000 1060000 1040000 1020000 1000000 7 0 0 2 / 7 / 9
7 0 0 2 / 8 / 9
7 0 0 2 / 9 / 9
7 0 0 2 / 0 1 / 9
7 0 0 2 / 1 1 / 9
7 0 0 2 / 2 1 / 9
7 0 0 2 / 3 1 / 9
7 0 0 2 / 4 1 / 9
7 0 0 2 / 5 1 / 9
Time Confidential 16 © Nokia Siemens Networks
7 0 0 2 / 6 1 / 9
7 0 0 2 / 7 1 / 9
7 0 0 2 / 8 1 / 9
7 0 0 2 / 9 1 / 9
7 0 0 2 / 0 2 / 9
7 0 0 2 / 1 2 / 9
7 0 0 2 / 2 2 / 9
7 0 0 2 / 3 2 / 9
Iub / Iur interface blocking (2/2) Example: Less VCI blocked with throughput based optimization Numb er of AAL2 CAC Rejected VCI 36
120000
Sum of AAL2_CAC_REJECTED (Aal2cac)
100000
80000
60000
40000
20000
0 7 0 0 2 / 7 / 9
7 0 0 2 / 8 / 9
7 0 0 2 / 9 / 9
7 0 0 2 / 0 1 / 9
7 0 0 2 / 1 1 / 9
7 0 0 2 / 2 1 / 9
7 0 0 2 / 3 1 / 9
7 0 0 2 / 4 1 / 9
7 0 0 2 / 5 1 / 9
7 0 0 2 / 6 1 / 9
7 0 0 2 / 7 1 / 9
7 0 0 2 / 8 1 / 9
7 0 0 2 / 9 1 / 9
7 0 0 2 / 0 2 / 9
7 0 0 2 / 1 2 / 9
7 0 0 2 / 2 2 / 9
7 0 0 2 / 3 2 / 9
Time
• Thanks to less AAL2 occupancy, the number of AAL2 CAD rejects reduced by more than half Confidential 17 © Nokia Siemens Networks
Features to reduce blocking (1/10) Feature list
RNC PS features Data highway • • • • • Confidential 18 © Nokia Siemens Networks
Priority Based Scheduling (PBS) Enhanced Overload Control Throughput Based Optimisation (TBO) Flexible Upgrade of NRT DCH Dynamic Link Optimisation (DyLo)
Features to reduce blocking (2/10) Priority Based Scheduling Existing NRT allocations can be downgraded or released if there are other users requesting initial capacity in the following congestion situations: PrxTotal > PrxTarget (Marginal Load Area) PtxTotal > PtxTarget (Marginal Load Area) Lack of DL spreading code Lack of BTS HW (CE)
bit rate
NRT RB 1
Reconfiguration of RB1
NRT RB 2
RT traffic Capacity request RB2 Confidential 19 © Nokia Siemens Networks
time
Features to reduce blocking (3/10) Example: PBS parameter settings for different test cases PBS Policy, Initial bit rate and PtxTarget vary between test cases
PtxTarget was changed either “favour” DL spreading code triggering or DL power triggering Initial bit rate was high, either 384 or 128 during test Iub user plane size was set smaller and HSDPA call was running, too *TC= Test Case
Confidential 20 © Nokia Siemens Networks
→ see
one result example in the appendix
Features to reduce blocking (4/10) Enhanced Priority Based Scheduling and Overload Control Downgrade or release NRT DCH in congested situation: • Priority Based Scheduling – Existing NRT allocations can be downgraded or released if there are other users requesting initial capacity in the congested situation – Prx/PtxTotal > Prx/PtxTarget (Marginal Load Area)
• Enhanced Overload Control – In an overload situation PS start modification or reconfiguration of
.
– Prx/PtxTotal > Prx/PtxTarget+ Prx/PtxOffset (Overload Area)
Overload Load Margin
Enhanced Overload control can be “deactivated” by setting PtxOffset to high value Confidential 21 © Nokia Siemens Networks
Enhanced Overload Control Priority Based Scheduling Normal load
Prx/Ptx Target+Prx/Ptx Offset Prx/Ptx Target [dB]
Features to reduce blocking (5/10) Priority Based Scheduling and Enhanced Overload Control KPIs
Confidential 22 © Nokia Siemens Networks
Features to reduce blocking (6/10) Throughput Based Optimisation and Flexible Upgrade of NRT DCH • RAN 409:Throughput based optimization of the PS algorithm adapts the DCH resource reservation to meet the actual utilization (or used bit rate) of the DCH. – TBO Downgrades UL/DL radio bearer allocation due to low throughput
• RAN 202: Flexible upgrade of NRT DCH data rate upgrades to higher bit rate only if current bit rate is fully utilised =>
– NRT PS radio bearer allocations will decrease for same amount of traffic – Average WBTS hardware resource (CE) usage for NRT will decrease – Iub AAL2 reservation and amount of AAL2 rejects (CAC) will decrease • Throughput based optimisation and flexible upgrade is very useful also for HSDPA associated uplink DPCH (enabled with DynUsageHSDPAReturnChannel parameter)
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Features to reduce blocking (7/10) Example: Downgrade causes without / with TBO
RB_DOWNGR_DUE_THRPOPT (Cellres) RB_DOWNGR_DUE_PRE_EMP_BTS (Cellres) RB_DOWNGR_DUE_PRE_EMP_AAL2 (Cellres) RB_DOWNGR_DUE_PBS_INTERF (Cellres) RB_DOWNGR_DUE_PBS_BTS (Cellres)
RB Downgrade Cause Distributions
RB_DOWNGR_DUE_PBS_AAL2 (Cellres) RB_DOWNGR_DUE_OLC_TFC_SUBS (Cellres) RB_DOWNGR_DUE_OLC_RL_RECONF (Cellres) RB_DOWNGR_DUE_DYLO_RL_POWER (Cellres)
1400000
• Most of RB downgrades /
1200000
releases are triggered by 1000000
reconfigurations) • At the same time, the triggers due to pre-emption and DyLo decrease significantly
800000
600000
400000
•
200000
→see
next slide
0 7 0 0 2 / 7 / 9
7 0 0 2 / 8 / 9
Confidential 24 © Nokia Siemens Networks
7 0 0 2 / 9 / 9
7 0 0 2 / 0 1 / 9
7 0 0 2 / 1 1 / 9
7 0 0 2 / 2 1 / 9
7 0 0 2 / 3 1 / 9
7 0 0 2 / 4 1 / 9
7 0 0 2 / 5 1 / 9
7 0 0 2 / 6 1 / 9
7 0 0 2 / 7 1 / 9
7 0 0 2 / 8 1 / 9
7 0 0 2 / 9 1 / 9
7 0 0 2 / 0 2 / 9
7 0 0 2 / 1 2 / 9
7 0 0 2 / 2 2 / 9
7 0 0 2 / 3 2 / 9
Features to reduce blocking (8/10) Example: Downgrade causes without / with TBO RB_RELEASE_DUE_PRE_EM P_BTS (Cellres)
RB Dow ngrade/Release due to Pre-emption or DyLo
RB_RELEASE_DUE_PRE_EM P_AAL2 (Cellres) RB_DOWNGR_DUE_PRE_EMP_BTS (Cellres)
40000
RB_DOWNGR_DUE_PRE_EMP_AAL2 (Cellres) RB_DOWNGR_DUE_DYLO_RL_POWER (Cellres)
35000
30000
25000
20000
15000
10000
5000
0 7 0 0 2 / 7 / 9
7 0 0 2 / 8 / 9
7 0 0 2 / 9 / 9
Confidential 25 © Nokia Siemens Networks
7 0 0 2 / 0 1 / 9
7 0 0 2 / 1 1 / 9
7 0 0 2 / 2 1 / 9
7 0 0 2 / 3 1 / 9
7 0 0 2 / 4 1 / 9
7 0 0 2 / 5 1 / 9
7 0 0 2 / 6 1 / 9
7 0 0 2 / 7 1 / 9
7 0 0 2 / 8 1 / 9
7 0 0 2 / 9 1 / 9
7 0 0 2 / 0 2 / 9
7 0 0 2 / 1 2 / 9
7 0 0 2 / 2 2 / 9
7 0 0 2 / 3 2 / 9
Features to reduce blocking (9/10) Example: Flexible upgrade parameter settings for different test cases • In Case of flexible upgrade, parameters are not changed during measurement – HTTP download cases are tested with flexible upgrade “on” and flexible upgrade “off” – HTTP download is also tested by setting initial bit rate same as maximum bit rate =384 When FlexUpgrUsage is set “on” and DCHUtilHighAveWin > 0, throughput measurement are activated
ex e upgrade of NRT DCH Data Rate feature is here now activated
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The parameters (TrafVolThresholdUL/DLHighBitRate) are in use if the Flexible Upgrade of NRT DCH Data Rate feature is activated by the FlexUpgrUsage parameter. Otherwise the traffic volume threshold for the uplink/downlink direction is defined by the TrafVolThresholdUL/DLHigh parameter.
Features to reduce blocking (10/10) Dynamic Link Optimization DyLo for NRT Traffic Coverage 128kbps
Ptx ave is averaged radio link
384kbps
power, measured and reported to RNC by BTS and checked in RNC against Ptx max (defined by
UE
Admission Control)
distance
PtxRL
Ptxmax Offset
Triggering of DyLO Ptxave Confidential 27 © Nokia Siemens Networks
time
Radio link is modified to use lower bit rate when Tx power of the radio link is getting close to maximum
Capacity optimization Monitoring of R99 Blocking issues
That’s blocking Confidential 28 © Nokia Siemens Networks
Capacity optimization Principles of capacity monitoring - Capacity bottlenecks - Reactive / proactive monitoring - RU20 Improvements
Monitoring of R99 blocking - Air interface TCP / RTWP - Channel Cards / Code Tree, - UTRAN interfaces Iub / Iur - Features to reduce blocking
Monitoring of HSPA congestion and blocking - Bottlenecks - HSDPA power consumption / CQI - Dynamic HSDPA power - Channel Cards / Code Tree - User Equipment
Confidential 29 © Nokia Siemens Networks
Bottlenecks (1/3) HSDPA setup failures ALLO_ HS _ DSCH _ FLOW _ INT + ALLO_ HS _ DSCH _ FLOW _ BGR+ DCH _ SEL_ MAX _ HSDPA_ USERS _ INT +
_ SEL_ MAX _ HSDPA_ USERS _ BGR+ REJ _ HS _ DSCH _ RET _ INT + REJ _ HS _ DSCH _ RET _ BGR+ + SETUP_ FAIL_ RNC _ HS _ DSCH _ INT + SETUP_ FAIL_ RNC _ HS _ DSCH _ BGR+ SETUP_ FAIL_ UE _ HS _ DSCH _ INT + + SETUP_ FAIL_ UE _ HS _ DSCH _ BGR+ SETUP_ FAIL_ BTS _ HS _ DSCH _ INT + SETUP_ FAIL_ BTS _ HS _ DSCH _ BGR+ + SETUP_ FAIL_ IUB_ HS _ DSCH _ INT + SETUP_ FAIL_ IUB_ HS _ DSCH _ BGR + DCH
RNC_614a=
∑
Capacity bottleneck analysis RNC_614 tells the HS_DSCH setup attempts => after this the HS-DSCH setup can fail due to: •
Too many simultaneous Users
•
Radio interface quality
•
BTS (lack of CE for UL)
•
Iub (lack of Iub for UL)
•
RNC (lack of DSP resources)
•
Iu-PS (lack of Iu-PS capacity)
•
IP-BB (lack of capacity on any “leased” IP-BB links)
•
UE (terminal problem)
Confidential 30 © Nokia Siemens Networks
RNC_614 HS-DSCH selections – the number of times when HS-DSCH has been selected by the PS scheduler Note that also the setup failures are included and also the success allocations Based on M1002 traffic counters In RU20 also the streaming counters in the formula
Bottlenecks (2/3)
RNC_914c – HSDPA setup success ratio – chapter 1 page 43 (packet level counters) RNC_609a – HSDPA success ratio - chapter 1 page 41 (retainabilty) RNC_608a – HSDPA data volume Iub – chapter 1 page 57
Example: HSDPA data volume versus HSDPA setup success Data volume MAC d (bytes)
Success rate (%)
7000000
100.000 98.000
6000000 96.000 5000000
94.000 92.000 90.000
3000000
88.000
2000000
1000000
No blocking yet
86.000
HSPA Success Ratio is bigger than RNC_614a
84.000
0
80.000
8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 . . . . . . . . . . . . . . . . . . . . 1 1 1 1 2 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 . . . . . . . 8 . 5 . 8 . 5 . 2 . 9 . 7 . 8 . 8 . 5 . 2 . 9 . 6 . 0 4 1 1 1 2 0 1 0 1 2 2 0 1 4 2 1 2 0 4 1 1 1 2 0 0 1
Confidential 31 © Nokia Siemens Networks
82.000
R NC _614a_HS -D SC H selections
R NC _608a_HS DP A data volum e (M AC -d) a t Iub
HSDPA Setup Success Ratio from user perspective
HSDPA Success Ratio from user perspective
Bottlenecks (3/3) Feature list to overcome bottlenecks RNC processing load Air interface TCP / RTWP
CPICH
Channel Cards, Code Tree WBTS
UTRAN interface load Iub/Iur
HSPA Data highway • • • • • Confidential 32 © Nokia Siemens Networks
Dynamic HSDPA Power Allocation MAC-hs Throughput CQI Management Dynamic NRT DCH Scheduling Dynamic Resource Allocation Dynamic HSDPA Code Allocation
HSDPA power consumption (1/3) HS-SCCH power control HS-SCCH inner loop power control algorithm • Node B estimates the HS-SCCH Tx power according to PHS-SCCH = PCPICH + Γ + λCQI + P0
– PCPICH CPICH power – Γ measurement power offset – λCQI power offset taken from CQICOMPENSATED by look up table (next slide) – P0 correction estimated by HS-SCCH outer loop power control algorithm • HS-SCCH Tx power – Estimated for each HSDPA connection individually – Updated with each CQI report
HS-PDSCH HS-PDSCH
High-Speed Physical DL Shared Channel High-Speed Physical DL Shared Channel
HS-SCCH HS-SCCH
Shared Control Channel for HS-DSCH Shared Control Channel for HS-DSCH
HS-DPCCH HS-DPCCH
Dedicated Physical Control Channel (UL) for HS-DSCH Dedicated Physical Control Channel (UL) for HS-DSCH
associatedDCH DCH associated Dedicated Channel Dedicated Channel
Confidential 33 © Nokia Siemens Networks
HSDPA power consumption (2/3) HS-SCCH power control example Example: PCPICH + Γ = 6 W (37.8 dBm) P0 = 0 CQI
TBS Throughput
λCQI
PHS-SCCH
4
317
-7.7 dB
(37.8 - 7.7) dBm = 30.1 dBm (1.0 W)
13
2279 1140 K
-16.6 dB
(37.8 - 16.6) dBm = 21.2 dBm (0.13 W)
159 K
Confidential 34 © Nokia Siemens Networks
HSDPA power consumption (3/3) Measurement power offset – initial HSDPA power • UE reports CQI assuming transmit power PHS-PDSCH SIG = PCPICH + Γ + Γ ∆ Γ – Γ calculated Γ by RNC Γ
Γ = Γ 0.7 (PtxMax – PtxNonHSDPA) – PCPICH Γ PtxMax = maximum cell power PtxNonHSDPA = total power allocated to R99 and DL control channels (latest report is taken)
– With Γ simplification to PHS-PDSCH SIG = (0.7 (Ptxmax – PtxNonHSDPA)) (dBm) + ∆ Γ Γ – Γ signalled Γ to UE in case of Γ
HS-DSCH setup Serving cell change
– actual CQI (only applied, if below 0) Example PtxMax = 20 W PtxNonHSDPA = 10 W Actual CQI = 24 UE class 6 ⇒ Maximum TBS = 7168 bit (Maximum of 5 HS-DSCH codes received ) Need CQI = 22 ⇒ ∆ = (22 - 24) dB = -2 dB 0.7 (PtxMax – PtxNonHSDPA) = 0.7 (20 W - 10 W) = 7 W = 38.5 dBm PHS-PDSCH SIG = 38.5 dBm - 2 dB = 36.5 dBm Confidential 35 © Nokia Siemens Networks
CQI Example: throughput versus CQI Huaw ei E870 Throughput (L1) v CQI PtxMaxHSDPA = 43dBm
N95 Throughput (L1) v CQI PtxMaxHSDPA=43dm
7000000
4000000
) 6000000 s / b ( t 5000000 u p h 4000000 g u o r h 3000000 T s h - 2000000 C A M1000000
) s / b ( 3000000 t u p 2500000 h g u 2000000 o r h T 1500000 s h C 1000000 A M 500000
3500000
0
0 5
10
15 Ave Reported CQI
20
25
0
5
10
15
20
25
Ave Reported CQI
Actual MACMAC-hs throughput characteristics are quite different, and idle TTIs are impacting. Samples sitting below the curves are typically in the slowslow start or servingserving-cell change periods.
Confidential 36 © Nokia Siemens Networks
30
Dynamic HSDPA power (1/10) HSDPA and non HSDPA power BTS periodically reports the total transmission power value PtxTotal and non-HSDPA power • “Transmitted carrier power of all codes not used for HS-PDSCH or HS-SCCH transmission ” if BTS supports only HSDPA or • non-HSPA power (“Transmitted carrier power of all codes not used for HS-PDSCH HS- SCCH E-AGCH E-RGCH or E-HICH transmission) if BTS supports HSUPA to RNC in RRI messages • These two are referenced as “HSxPA ower” The reported values are in range 0…100% representing the power value relative to the cell maximum transmission power, defined by MIN[PtxCellMax, MaxDLPowerCapability ] From the difference of reported PtxTotal and HSxPA power, RNC can calculate the used HSPApower value and update that to statistics counters • The counters are updated only when there is at least one HSDPA allocation in the cell RNC updates the HSxPA power value counters when nbap_radio_resource_ind_s message including PtxTotal and HSxPA power information is received from BTS and there is at least one HSDPA allocation in the cell. The unit for all counter updates is watt
Confidential 37 © Nokia Siemens Networks
Dynamic HSDPA power (2/10) Dynamic NRT DCH load target RNC affects the HSDPA power allocation indirectly by scheduling NRT DCH bit rates When there is at least one HS-DSCH MAC-d flow allocated in the cell, PtxTargetPS is used for packet scheduling and handover control purposes (this was PtxTargetHSDPA for R99 in RAS5.1) PtxTargetPS is adjusted between PtxTargetPSMin and PtxTargetPSMax
PtxTargetPSMin ≤ PtxTargetPS ≤ PtxTargetPSMax PtxTargetPSAdjustPeriod defines the adjustment period for the PtxTargetPS in terms of Radio Resource Indication (RRI) reporting periods If PtxTargetPSMax and PtxTargetPSMin are set to the same value, RNC does not adjust PtxTargetPS Dynamic NRT DCH scheduling disabled
Confidential 38 © Nokia Siemens Networks
Dynamic HSDPA power (3/10) Power congestion Adjustment of the PtxTargetPS is executed when power congestion for DL transport channel type (HS-DSCH or NRT DCH) is detected by the RNC The definition of the power congestion for DL transport channel type in this context is defined as follows • Power congestion for DL HS-DSCH transport channel type is detected when the following condition is effective: – PtxTotal ≥ PtxHighHSDPAPwr
• Power congestion for DL DCH transport channel type is detected when the following condition is effective: – PtxNonHSPA ≥ (PtxTargetPS – Offset) – Fixed value 1 dB used for Offset
Confidential 39 © Nokia Siemens Networks
Dynamic HSDPA power (4/10) Adjustment of dynamic NRT DCH load target Initial value of the PtxTargetPS is the lower from the following ones: PtxTarget or PtxTargetPSMax • Initial value is taken into use when the first HS-DSCH MAC-d flow is setup • Usage ends when the last HS-DSCH MAC-d flow is deleted • PtxTarget remains as a target for non-controllable load even if there are one or more HSDSCH MAC-d flows setup in the cell PtxTargetPS is adjusted based on received PtxTotal (Transmitted Carrier Power) and
• PtxNonHSPA = Transmitted carrier power of all codes not used for HS-PDSCH, HSSCCH, E-AGCH, E-RGCH or E-HICH transmission PtxTargetPS is adjusted only when there are NRT DCH users - in addition to the HS-DSCH MAC-d flow(s) - in the cell. Adjustment of the PtxTargetPS is done in fixed steps, defined by the PtxTargetPSStepUp and PtxTargetPSStepDown management parameters
Confidential 40 © Nokia Siemens Networks
Dynamic HSDPA power (5/10) Dynamic power share With no active HSDPA users: 1) NRT DCH scheduling to the PtxTarget+PtxOffset &RT DCH admission to PtxTarget
With active HSDPA users: 2) NRT DCH scheduling to PtxTargetPS 3) RT DCH admission to PtxTarget
HSDPA active
No HSDPA users
No HSDPA users PtxMax
PtxTotal 3
PtxTarget +PtxOffset
1 PtxTargetPS
2
PtxNRT PtxNonHSPA PtxNC Confidential 41 © Nokia Siemens Networks
Dynamic HSDPA power (6/10) HSDPA Congestion 1) HSDPA power congestion, if Ptxtotal ≥ PtxHighHSDPAPwr
Decrease by PtxTargetPSStepDown in case of HSDPA congestion
PtxMax 43 dBm PtxHSDPA
PtxHighHSDPAPwr -10..50; 0.1; 41 dBm
PtxTotal -10..50; 0.1; 40 dBm
PtxTargetPS
PtxTargetPSMin -10..50; 0.1; 36 dBm
PtxNonHSDPA
PtxNRT PtxNC
High threshold of PtxTotal for dynamic HSDPA pwr alloc: PtxHighHSDPAPwr (WCEL) (-10..50 dBm) (∆ = 0.1 dB) (41 dBm) Confidential 42 © Nokia Siemens Networks
Dynamic HSDPA power (7/10) DCH Congestion 2 ) NRT DCH power congestion
PtxNonHSDPA ≥ PtxTargetPS - 1dB (hard coded margin)
Increase PtxTargetPS up
to PtxTargetPS ideal
Increase by PtxTargetPSStepUp in case of DCH congestion PtxMax 43 dBm PtxHSDPA
PtxHighHSDPAPwr
PtxTotal PtxTargetPSMax
PtxTargetPS
2
PtxTargetPSMin
PtxNonHSDPA
PtxNRT PtxNC
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Dynamic HSDPA power (8/10) Summary: congestion situations
HSDPA active
1
PtxMax
PtxHSDPA
PtxTotal
PtxHighHSDPAPwr PtxTarget +PtxOffset
PtxTargetPSMax
PtxTargetPSTarget
PtxTargetPS
PtxTargetPSMin
2 PtxNonHSPA
PtxNRT PtxNC
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Dynamic HSDPA power (9/10) Calculation of ideal load target Target (ideal) value for the PtxTargetPS is calculated for each adjustment period defined by the management parameter PtxTargetPSAdjustPeriod Target (ideal) value for the PtxTargetPS is calculated as follows (in a linear fashion): PtxTargetPSTarget = MAX {MIN {P tx_nc + [(P max - P tx_nc ) x Weight Ratio ], PSMax }, PSMin }
Current available power for NRT DCH + HSDPA
• • Ptx_nc is the total non-controllable transmitted DL power • PSMax is the maximum allowed value for PtxTargetPS defined by the management parameter PtxTargetPSMax • PSMin is the minimum allowed value for PtxTargetPS defined by the management parameter PtxTargetPSMin • WeightRatio is the relative weight of DCH , i.e. WeightDCH / (WeightHSDPA + WeightDCH) – WeightHSDPA is the summed weight of the HS-DSCH radio access bearers (MAC-d flows) and WeightDCH is the summed weight of the NRT DCH radio access bearers Confidential 45 © Nokia Siemens Networks
Dynamic HSDPA power (10/10) Limitation of dynamic HSDPA power • HSDPA power is limited by the PtxMaxHSDPA parameter even with DRA • PtxMaxHSDPA should be increased from RAS5.1 value close or equal to Cell Maximum Tx Power for efficient HSDPA resources with DRA • Without DRA Max HSDPA power =min(PtxMaxHSDPA, PtxMax PtxTargetHSDPA) Ptx
Cell maximum TX power
PtxCellMax = 46 dBm (40W WPA)
HSDPA
Non-HSDPA power
Time
Common chs
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Maximum HSDPA power (PtxMaxHSDPA) Dynamic Resource-Allocation: DRA
Channel Cards Example: Setup failures versus BTS WSP resource 140
Occupation of Channel Elements (CE usage)
120
100
There is clear correlation between UL CE usage and HSDSCH Setup Failures • When max usage of CEs drops to the level 124 (from max 128) the SETUP_FAIL_BTS_HS_DSCH_
80 _
Elements moves to maximum - then Setup_Fail_BTS increases
60
_
_
MAX_USED_CE_UL (Wbtshw) SETUP_FAIL_BTS_HS_DSCH_BGR (Traffic)
• BGR drops significantly – 64/128 kbps UL return channel
40
will require 4 CEs in UL – Less fails with RAS06 16 kbits/s return channel (1 CE required)
20
0 1
16 31 46 61 76 91 106 121 136 151 166 181 196 211 226 241 256 271 286 301 316 331
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(CE utilisation period)
Code Tree (1/4) Maximum code allocation with HSUPA • Allocation of 15 is not possible when HSUPA is enabled in the cell SF=1 SF=2 SF=4 SF=8 SF=16 14 HS-PDSCH codes
SF=32 SF=64
Codes for common channels in the cell
Codes for associated DCHs and non-HSDPA users
SF=128 SF=256
Up to three HSSCCH codes
E-AGCH (256)
E-RGCH/E-HICH (128) Confidential 48 © Nokia Siemens Networks
Code Tree (2/4) SF128 code occupancy versus number of codes for HSDPA With similar calculations it the results are with 10 codes 86 codes blocked from SF128 (67.2 %) with 14 codes 119 codes blocked 99.2 from SF128 (93 %)
120
100
93 86.7
% y 80 c n a p u c c 60 e d o c 8 40 2 1 F S
80.5 74.2 67.2 60.9
SF128 occupancy
54.7
ree
48.4
co es
42.2 31
35.2 20
20
18
16
14
12
10
8
3.1
6
4
2
0
13
14
15
0 0
5
6
7
8
9
10
11
12
Number of allocated HS-PDSCH codes
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Code Tree cupancy.xls (122 K.
Code Tree (3/4) Code congestion
• RNC downgrades HS-PDSCH code(s) due to DPCH code congestion • RNC does not downgrade HS-PDSCH codes lower than the minimum allowed number of HS-PDSCH codes
• If RT request is congested due to lack of DPCH code(s), HS-
• If NRT DCH scheduling is congested due to lack of DPCH
•
code(s), HS-PDSCH codes are downgraded in order to admit NRT DCH request IF # HS-PDSCH codes > Maximum code set DPCHOverHSPDSCHThreshold The number of HS-PDSCH codes after downgrade will be the highest possible from the HS-PDSCH code set
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Code Tree (4/4) HS-DSCH code downgrade parameters s e d o c 8 2 1 F S d e v r e s e r f o r e b m u
s e d o c 6 1 F S d e t a c o l l a f o r e b m u N
128 118 108 98 88 78 68 58 48 38 0 15 14 13 12 11 10 9 8 7 6 5
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HSPDSCHMarginSF128
Periodical HS-DSCH code downgrade if the number of currently available SF128 codes is lower than HSPDSCHMarginSF128 (default 8) HS-DSCH code downgrade due
Maximum in code set DPCHOverHSPDSCHThreshold
allowed if number of currently allocated HS-PDSCH codes is greater than maximum code set DPCHOverHSPDSCHThreshold (default 0, no downgrade possible due to NRT congestion !!!)
User Equipment Example: Throughput per UE Type and PtxMaxHSDPA Nokia N95 • Category 6 terminal
Throughput CDF v U E Type & PtxMaxHSDPA
• 16QAM modulation • Support a max of 5 codes
1 0.9
• Max theoretical throughput ~3.6 Mbps
0.8 0.7 E870 39dBm
0.6
% F 0.5 D C
E870 43dBm N95 39dBm
0.4
N95 43dBm
0.3
Huawei E 870
0.2 0.1
• HSDPA Category 8 terminal
0 0
0 0 5
0 0 0 1
0 0 5 1
0 0 0 2
0 0 5 2
0 0 0 3
0 0 5 3
0 0 0 4
0 0 5 4
0 0 0 5
0 0 5 5
0 0 0 6
0 0 5 6
Throughput (kb/s)
• HSUPA Category 5 terminal • 16QAM modulation • Support a max of 10 codes • Max theoretical throughput ~7.2Mbps
Gain for N95 ~ 150kb/s with higher HSDPA power For E870 gain is higher ~ 500kb/s Confidential 52 © Nokia Siemens Networks
Capacity optimization Monitoring of HSPA Blocking
That’s blocking in HSPA
Confidential 53 © Nokia Siemens Networks
Appendix
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Presentation / Author / Date
Example result with TC 1: Initial 384, PBSPolicy “any” PtxTarget 40 Add PS NRT Background class bearers until PBS triggers. Monitor which bearer is downgraded and verify PBS triggering reason from the counters Please note that because the PtxTarget is 40dBm then the reason for PBS in this case is the code congestion
Bearers in allocation order
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5th Incoming PS DCH downgrade first one due the Spreading code congestion => Longest allocation time
TBO Examplre- RB Downgrade RB_DOWNGR_DUE_THRPOPT (Cellres) RB_DOWNGR_DUE_PRE_EMP_BTS (Cellres) RB_DOWNGR_DUE_PRE_EMP_AAL2 (Cellres) RB_DOWNGR_DUE_PBS_INTERF (Cellres) RB_DOWNGR_DUE_PBS_BTS (Cellres)
RB Downg rade Cause Distributions
RB_DOWNGR_DUE_PBS_AAL2 (Cellres) RB_DOWNGR_DUE_OLC_TFC_SUBS (Cellres) RB_DOWNGR_DUE_OLC_RL_RECONF (Cellres) RB_DOWNGR_DUE_DYLO_RL_POWER (Cellres)
1400000
1200000
1000000
800000
600000
400000
200000
0 7 0 0 2 / 7 / 9
7 0 0 2 / 8 / 9
7 0 0 2 / 9 / 9
7 0 0 2 / 0 1 / 9
7 0 0 2 / 1 1 / 9
7 0 0 2 / 2 1 / 9
7 0 0 2 / 3 1 / 9
7 0 0 2 / 4 1 / 9
7 0 0 2 / 5 1 / 9
7 0 0 2 / 6 1 / 9
7 0 0 2 / 7 1 / 9
7 0 0 2 / 8 1 / 9
7 0 0 2 / 9 1 / 9
7 0 0 2 / 0 2 / 9
7 0 0 2 / 1 2 / 9
7 0 0 2 / 2 2 / 9
7 0 0 2 / 3 2 / 9
RB_RELEASE_DUE_PRE_EMP_BTS (Cellres)
RB Dow ngrade/Release due to Pre-emption or DyLo
RB_RELEASE_DUE_PRE_EMP_AAL2 (Cellres) RB_DOWNGR_DUE_PRE_EMP_BTS (Cellres)
40000
RB_DOWNGR_DUE_PRE_EMP_AAL2 (Cellres) RB_DOWNGR_DUE_DYLO_RL_POWER (Cellres)
35000
30000
25000
20000
15000
10000
5000
0 7 0 0 2 / 7 / 9
7 0 0 2 / 8 / 9
7 0 0 2 / 9 / 9
7 0 0 2 / 0 1 / 9
7 0 0 2 / 1 1 / 9
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7 0 0 2 / 2 1 / 9
7 0 0 2 / 3 1 / 9
7 0 0 2 / 4 1 / 9
7 0 0 2 / 5 1 / 9
7 0 0 2 / 6 1 / 9
28.2.2008
7 0 0 2 / 7 1 / 9
7 0 0 2 / 8 1 / 9
7 0 0 2 / 9 1 / 9
7 0 0 2 / 0 2 / 9
7 0 0 2 / 1 2 / 9
7 0 0 2 / 2 2 / 9
7 0 0 2 / 3 2 / 9
• Most of RB downgrades / releases are triggered by throughput base optimisation; • At the same time, the triggers due to pre-emption and DyLo decreased significantly;
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