Upload
dseprio
View
429
Download
75
Tags:
Embed Size (px)
Citation preview
1. RAN_Parameter Configuration1. RAN_Parameter Configuration2. Main RAN_Parameter Grouping based on Functionality2. Main RAN_Parameter Grouping based on Functionality3. Specific HSDPA Parameter3. Specific HSDPA Parameter
HSDPA and RAN ParametersHSDPA and RAN ParametersTelkomsel Jabotabek 3G NetworkTelkomsel Jabotabek 3G Network
Company Confidential2 © Nokia Siemens Networks
RAN_Parameter Configuration
Company Confidential3 © Nokia Siemens Networks
Logical Structure of the RNC Database Objects
RNC
WBTS
WCELADJS
HOPS
ADJG
HOPG
FMCG
ADJI
HOPI
FMCI
FMCS
COCO
WANE
WSG
WLCSE
WSMLC
Company Confidential4 © Nokia Siemens Networks
Managed Object types
• RNC = Radio Network Controller
• WBTS = WCDMA Base Station
• WCEL = WCDMA Cell
• ADJ = Adjacency for WCDMA cell
• ADJS = intra-frequency adjacency
• ADJI = inter-frequency adjacency
• ADJG = inter-system adjacency
• HOP = Handover Path
• HOPS, HOPI, HOPG
• FMC = Frequency Measurement Control
FMCS, FMCI, FMCG
• COCO = Radio Network Connection Configuration
• WANE = WCDMA Authorized Network
• WSG = WCDMA subscriber group
• WLCSE = WCDMA Location service entity
• WSMLC = WCDMA Serving Mobile Location Center
Company Confidential5 © Nokia Siemens Networks
Parameter Count
Ref: RAN05 (RN2.1) parameter dictionary
Parameter count GroupMO Class AC HC Ident LC PC PS SI Other Grand TotalADJG 14 1 1 16ADJI 16 1 1 18ADJS 17 1 1 19COCO 2 82 84FMCG 22 1 9 32FMCI 22 1 9 32FMCS 21 1 9 31HOPG 8 1 9 18HOPI 15 1 9 25HOPS 16 1 9 26RNC 53 8 30 1 16 51 26 96 281WANE 8 9 17WBTS 9 5 2 6 19 21 62WCEL 27 13 12 12 17 23 45 53 202WLCSE 6 34 40WSG 8 9 17WSMLC 1 12 13Grand Total 89 193 62 19 33 93 71 373 933
Company Confidential6 © Nokia Siemens Networks
Main RAN_Parameter Grouping based on Functionality
Company Confidential12 © Nokia Siemens Networks
Main RAN_Parameter Grouping
• Idle Mode: Cell Selection/ Re-selection
• RRC Connection Establishment
• RAB Establishment
• Handovers
Company Confidential13 © Nokia Siemens Networks
• WCEL: QrxlevMin (-115 dBm)•The minimum required RX level in the cell. •This parameter is part of SIB 3.•[-115 ... –25] dBm, step 2 dBm; default: -115 dBm.
• WCEL: QqualMin (-18 dB)•The minimum required quality level in the cell (Ec/No). •This parameter is part of SIB 3.•[-24 ... 0] dB, step 1 dB, default: -18 dB.
• WCEL: UEtxPowerMaxPRACH (21 dBm)•This parameter defines the maximum transmission power level a UE can use on PRACH. •The value of the parameter also effects the cell selection and reselection procedures. •The value of the parameter is sent to UE in the Cell selection and re-selection of SIB 3 and 4 of the serving cell.[..]
Cell Selection Parameters
Company Confidential14 © Nokia Siemens Networks
• WCEL: UseOfHCS (0)•This parameter indicates whether the serving cell belongs to a Hierarchical Cell Structure (HCS). •This parameter is part of SIB 11/12.•0 (HCS not used), 1 (HCS in use); default: 0.
• WCEL: Sintrasearch (10 dB)•The threshold for intra-frequency measurements, and for the HCS measurement rules.•This parameter is part of SIB 3.•[0 ... 20] dB, step 2 dB, default: 10 dB.
• WCEL: Sintersearch (8dB)•The threshold for inter-frequency measurements, and for the HCS measurement rules.•This parameter is part of SIB 3.•[0 ... 20] dB, step 2 dB, default: 8 dB.
• WCEL: Ssearch_RAT (4dB)•The RAT-specific threshold for inter-RAT measurement rules. •This parameter is part of SIB 3.•[0 ... 20] dB, step 2 dB, default: 4 dB.
Cell Reselection Parameters (1/6)
Company Confidential15 © Nokia Siemens Networks
• WCEL: SHCS_RAT •The RAT specific threshold for inter-RAT measurement rules. •This parameter is part of SIB 3.•[-1 ... 91] dB, step 2 dB, default: -1 dB (UE sets this value to 0).
• WCEL: Slimit_SearchRAT •Threshold for skipping inter-RAT measurement rules in HCS. •Above this RAT specific threshold in the serving UTRA cell, the UE does not need to perform any inter-RATm measurements. •This parameter is part of SIB 3.•[0 ... 20] dB, step 2 dB, default: 2 dB.
• WCEL: SsearchHCS •Threshold for intra- and inter-frequency measurement rules in HCS. •Below this limit in the serving cell, the UE initiates measurements of all intra and inter-frequency neighbouring cells of the serving cell. •This parameter is part of SIB 3.•[-1 ... 91] dB, step 2 dB, default: -1 dB (UE sets this value to 0).
Cell Reselection Parameters (2/6) With HCS
Company Confidential16 © Nokia Siemens Networks
• WCEL: NCr •This parameter defines the maximum number of cell reselections.•If the number of cell reselections during the TCrmax time period exceeds the value of NCr, high mobility has been detected. •Not used if TCrmax equals 'not used’.•This parameter is part of SIB 3.•[1 ... 16], default: 8.
• WCEL: TCrmax•The duration for evaluating the allowed amount of cell reselections. •If the number of cell reselections during the time period defined by Tcrmax exceeds Ncr, high mobility has been detected. •This parameter is part of SIB 3.•[0 (= not used), 30, 60, 120, 180, 240] seconds, default: 60 seconds.
• WCEL: TCrmaxHyst•Cell reselection hysteresis for reverting from UE high-mobility measurements.•The additional time period before UE reverts to low-mobility measurements.•This parameter is part of SIB 3.•[0, 10, 20, 30, 40, 50, 60, 70] seconds, default: 0 seconds.
Cell Reselection Parameters (3/6) With HCS
Company Confidential17 © Nokia Siemens Networks
• WCEL: HCS_PRIO•This parameter defines the HCS priority level for a cell. •Value 0 indicates the lowest HCS priority and value 7 indicates the highest HCS priority.•[0 ... 7], default: 0.
• WCEL: QHCS•Quality threshold level for applying prioritised hierarchical cell re-selection for a cell. •Part of HCS Serving cell information (Qhcss). •This parameter is part of SIB 3. •[-24 ... 0] dB, step 0.5 dB, default: -24 dB.
• HOPS: AdjsHCSthreshold•Defines the threshold level which must be exceeded by the CPICH Ec/No of the intra-frequency neighbouring cell before the hierarchical cell re-selection becomes possible (Qhcsn).•[-24 ... 0] dB, step 0.5 dB, default: -24 dB.
• HOPI: AdjiHCSthreshold: •[-24 ... 0] dB, step 0.5 dB, default: -24 dB.
• HOPG: AdjgHCSthreshold: •[-110 ... -37] dBm, default: -110 dBm.
Cell Reselection Parameter (4/6) With HCS
Company Confidential18 © Nokia Siemens Networks
• HOPS: AdjsTempOffset1•This parameter is used in the cell ranking between cells when the intra-frequency neighbour cell has the same HCS priority level as the serving cell. •[3, 6, 9, 12, 15, 18, 21, 100 (Infinity)] dB, default: 3 dB. •HOPI: AdjiTempOffset1, •HOPG: AdjgTempOffset1
• HOPS: AdjsTempOffset2•This parameter is used in the cell ranking between WCDMA cells when the intra-frequency neighbour cell has the same HCS priority level as the serving cell. •[2, 3, 4, 6, 8, 10, 12, 100 (Infinity)] dB, default: 2 dB. •HOPI: AdjiTempOffset2
• HOPS: AdjsPenaltyTime•Defines the time period during which the Temporary Offset 1/2 is applied in the cell re-selection procedure for the intra-frequency neighbour cell in question.•[0 ... 60] seconds, step 10 seconds, default: 0.•HOPI: AdjiPenaltyTime, •HOPG: AdjgPenaltyTime
Cell Reselection Parameter (5/6) With HCS
Company Confidential19 © Nokia Siemens Networks
• WCEL: Qhyst1 (Qhyst2) (0)• Qhyst1 is used for TDD and GSM cells, and for FDD cells when cell
selection and re-selection quality measure is set to CPICH RSCP (CPICH Ec/No) (Qhyst1s/ Qhyst2s).
• This parameter is part of SIB 3.• [0 ... 40] dB, step 2 dB, default: 4 dB.
• HOPS: AdjsQoffset1 (AdjsQoffset2) (0) • This parameter is used in the cell re-selection and ranking between
WCDMA cells. • The value of this parameter is subtracted from the measured CPICH RSCP
(CPICH Ec/No) of the intra-frequency neighbour cell before the UE compares the quality measure with the cell re-selection/ranking criteria.
• [-50 ... 50] dB, default: 0 dB. • HOPS: AdjsQoffset1 (AdjsQoffset2), HOPG: AdjgQoffset1,
(AdjgQoffset2)
• WCELL: Treselection (2s)• The UE triggers the reselection of a new cell if the cell reselection criteria
are fulfilled during the time interval Treselection.• This parameter is part of SIB 3.• [0 ... 31] seconds, default: 0 seconds.
• The remaining parameters were already specified under Nokia Parameters for Cell Reselection (Part IV).
Cell Reselection Parameter (6/6)
Company Confidential20 © Nokia Siemens Networks
Cell Reselection BSS-Parameter (1/3)
• Qsearch_I (7 always) and Qsearch_P (7 always) define the threshold for non-GPRS/GPRS (respectively) capable UEs to measure 3G neighbour cells when a running average of the received downlink signal level (RLA_C) of the serving cell is below (0-7) or above (8-15) the threshold
Value 0 1 … 6 7 8 9 10 … 14 15
dBm -98 -94 … -74 Always -78 -74 -70 … -54 Never
• FddQoffset (-32)and FddGprsOffset (-32) the non-GPRS/GPRS (respectively) capable UEs add this offset to the RLA_C of the GSM cells. After that the UE compares the measured RSCP values of 3G cells with signal levels of the GSM cellsValue 0 1 2 3 … 8 … 14 15
dBm -32 (infinity)
-28 -24 -20 … 0 … 24 28
Always select irrespective of
RSCP value
Reselect in case RSCP > GSM RXLev
(RLA_C) +28dB
If RLA_C < -94 UE starts 3G
measurements
UE always measures 3G cells
UE never measures 3G cells
If RLA_C > -70 UE starts 3G
measurements
Company Confidential21 © Nokia Siemens Networks
Cell Reselection BSS-Parameter (2/3)• FddQmin(-12), defines minimum Ec/No threshold that a 3G cell must
exceed, in order the UE makes a cell reselection from 2G to 3G. This is the new mapping table
• FDD_REP_QUANT defines the reporting quantity for UTRAN cell (1=Ec/No or 0=RSCP, default 1). This parameter is hidden and it can not be tuned
• 3G_Search_PRIO parameter allows to extend the BSIC reporting interval from 10 s to 13s by checking the BSICs from non-serving BCCH carriers and also make WCDMA measurements as often as possible. Range is 0=no, 1=yes, default value .This parameter is hidden and it can not be tuned
Defined in the SI2quater and PSI3quater if PBCCH is allocatedParameterParameter
Name for Sys Info (SI)
Name for Sys Info (SI)
Qsearch_IQsearch_I
2quater2quater
Qsearch_PQsearch_P Qsearch_PQsearch_P
2quater2quater 3quater3quater
FDD_QMinFDD_QMin
2ter2ter
FDD_(GPRS)Qoffset
FDD_(GPRS)Qoffset
2quater2quater
FDD_REP_QUANT
FDD_REP_QUANT
2ter2ter
3G_search_PRIO
3G_search_PRIO
2(3)quarter(PBCCH)
2(3)quarter(PBCCH)
Fdd_Qmin mappingAif parameter 0 1 2 3 4 5 6 7Fdd_Qmin (old) [dB] -20 -19 -18 -17 -16 -15 -14 -13Fdd_Qmin (new) [dB] -20 -6 -18 -8 -16 -10 -14 -12
Company Confidential22 © Nokia Siemens Networks
Cell Reselection BSS-Parameter (3/3)
Parameter Specification name
Nokia parameter
Range/Default value
Recommended value
GPRS threshold to search WCDMA RAN cells (QSRP)
Qsearch_P qSearchP 0…15/15 (never)
7 (always)
threshold to search WCDMA RAN cells (QSRI)
Qsearch_I qSearchI 0…15/15 (never)
7 (always)
GPRS fdd cell reselect offset (GFDD)
FDD_GPRS_Qoffset
FddGprsQoffset
-32…28 dB/ -32 (infinity)
Same as default
FDD cell reselect offset (FDD) FDD_Qoffset FddQoffset -32…28 dB/ -32 (infinity)
Same as default
minimum fdd threshold (FDM) FDD_Qmin FddQmin 0…7 / 7 (-12 dB)
Same as default
Specification name Parameter explanation Value range Note
FDD_REP_QUANT Indicates the reporting quantity for UTRAN FDD cells
0 = RSCP, 1 = EC/NO
Not tunable, Fixed value 1
3G_SEARCH_PRIO Indicates if 3G cells may be searched when BSIC decoding is required
0 = no, 1 = yes
Not tunable, Fixed value 1
Ch
an
geab
leH
idd
en
Company Confidential23 © Nokia Siemens Networks
SintrasearchSintersearchSsearchRAT m
No need to measure
neighbour cells
Intra- frequency
Sx=Squal (in FDD mode)
Intra-frequencyInter-frequency
serving cell
Example: Nokia Qqualmin = -18 dB, Sintrasearch = 10dB, Sintersearch = 8dB,Ssearch_RAT = 4dB
When to perform measurements
Intra-frequency
Inter-freqencyInter-RAT
Cell Reselection: Measurement RulesWithout HCS
-8 dB-10 dB-14 dBEC/N0 =
Company Confidential24 © Nokia Siemens Networks
Cell Reselection Criterion
Re-selection if not serving cell
Company Confidential25 © Nokia Siemens Networks
Qqualmeas (dB)(CPICH Ec/N0)
Qrxlevmeas (dBm)CPICH RSCP
Qqualmin(–24...0)
Qrxlevmin(–115...–25)
Srxlev > 0Pcompensation
Squal > 0 S-Criterionfulfilled
Squal >0 ANDSrxlev > 0
suitable
cell?
Cell Selection Criterion S (in the FDD mode)
Squal = Qqualmeas – Qqualmin
Srxlev = Qrxlevmeas - Qrxlevmin – Pcompensation
Pcompensation = max(UE_TXPWR_MAX_RACH – P_MAX, 0) (dB)
Company Confidential27 © Nokia Siemens Networks
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP/GSM RSSI + Qhyst1Rn= CPICH_RSCP(n) or RXLEV(n) - Qoffset1
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP/GSM RSSI + Qhyst1Rn= CPICH_RSCP(n) or RXLEV(n) - Qoffset1
Rn higher in GSM cellRn higher in GSM cellYes No
Cell re-selection to GSM
Cell re-selection to GSM
Second ranking only for WCDMA cells based on CPICH Ec/No
Rs = CPICH Ec/No + Qhyst2Rn= CPICH Ec/No -Qoffset2
Second ranking only for WCDMA cells based on CPICH Ec/No
Rs = CPICH Ec/No + Qhyst2Rn= CPICH Ec/No -Qoffset2
Cell re-selection to WCDMA cell of highest
R value
Cell re-selection to WCDMA cell of highest
R value
GSM cell measurements
available If :
CPICH Ec/No - QqualMin < Ssearch_RAT
Rs = Serving WCDMA cell
calculation, with
hysteresis parameter
Rn = Neighbour WCDMA or GSM cell calculation with offset parameter
GSM cell measurements
available If :
CPICH Ec/No - QqualMin < Ssearch_RAT
Rs = Serving WCDMA cell
calculation, with
hysteresis parameter
Rn = Neighbour WCDMA or GSM cell calculation with offset parameter
If a TDD or GSM cell is ranked as the best cell, then the UE must perform cell re-selection to that TDD or GSM cell.
If a FDD cell is ranked as the best cell and cell_selection_and_reselection-quality_measure is set to CPICH RSCP, the UE shall perform cell re-selection to that FDD cell.
If a FDD cell is ranked as the best cell and cell_selection_and_reselection-quality_measure is set to CPICH Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria using the measurement quantity CPICH Ec/No calculating the R values of the FDD cells.
Cell Reselection Algorithm from 3G to 2G
Qhyst1 = 0 dB
AdjsQoffset1 = 0 dB
QqualMin = -18 dB
SsearchRAT = 4 dB
AdjgQoffset1 = 0 dB
AdjgQrxlevMin = -101 dBm
Qhyst2 = 2 dB
AdjsQoffset2 = 0 dB
RS
CP
RS
SI
Company Confidential29 © Nokia Siemens Networks
Cell Reselection Algorithm from 2G to 3G
Cell Reselection List
WCDMA cellreselection
BCCH: FddQmin, FddQOffset
DEFAULT:fdd cell reselect offset:
select always (value is -infinity)
minimum fdd threshold = -12 dB
DEFAULT:fdd cell reselect offset:
select always (value is -infinity)
minimum fdd threshold = -12 dB
Check levels every 5s from serving GSM cell
and best 6 GSM neighbour cells
UE starts WCDMA measurements if Rxlev running average (RLA_C) is below or above
certain threshold:RLA_C QsearchI or QsearchP
aveRxLev < Qsearch
UE starts WCDMA measurements if Rxlev running average (RLA_C) is below or above
certain threshold:RLA_C QsearchI or QsearchP
aveRxLev < Qsearch
UE can select WCDMA cell if the level of the serving GSM and non-serving GSM cells has been
exceeded by certain offset for a period of 5 s:CPICH RSCP > RLA_C + FddQoffset
RSCP > (aveRxLev) + -32
UE can select WCDMA cell if the level of the serving GSM and non-serving GSM cells has been
exceeded by certain offset for a period of 5 s:CPICH RSCP > RLA_C + FddQoffset
RSCP > (aveRxLev) + -32
UE will re-select WCDMA cell in case it's quality is acceptable:
CPICH Ec/No FddQminEcNo -8
UE will re-select WCDMA cell in case it's quality is acceptable:
CPICH Ec/No FddQminEcNo -8
Compare levels of all GSM cells
to WCDMAneighbour
Check quality of neighbour
WCDMA cells, no priorities between
WCDMA neighbours
05
.08
:Th
is m
ay
take
up
to
30
s
Qsearch = 7(always)
FddQoffset = -32 dB
FddQmin = -8 dB
Company Confidential31 © Nokia Siemens Networks
Main RAN_Parameter Grouping
• Idle Mode: Cell Selection/ Re-selection
• RRC Connection Establishment
• RAB Establishment
• Handovers
Company Confidential33 © Nokia Siemens Networks
RRC Connection Establishment UE-RAN
• The power level for sending of the RRC Connection Request message is set/calculated by the UE
• In average coverage conditions the RRC Connection Setup performance can be improved by tuning the open loop power control parameters
• These parameters are
• PRACH_preamble_retrans (7) & RACH_tx_Max (16dB)
• PowerOffsetLastPreamblePRACHmessage(2dB))
• PowerRampStepPRACHpreamble (2 dB)
• ptx = PtxPrimaryCPICH(30/33)-RSCP(CPICH) +RSSI(BS) + " PRACHRequiredReceivedCI “(25)
Company Confidential34 © Nokia Siemens Networks
RRC Connection Establishment UE-RAN
• If no acquisition indicator is received UE raises the transmission power by PowerRampStepPRACHpreamble which is a broadcast parameter
• This procedure is repeated until acquisition indicator is received, after which UE send the RACH message at power which offset by PowerOffsetLastPreamblePRACHmessage from the last preamble
• PRACH_preamble_retrans parameter determines how many times PRACH preamble can be sent within one preamble ramping cycle (SIB5&6)
• RACH_tx_Max defines how many times the PRACH preamble ramping cycle procedure can be repeated before UE MAC reports a failure on RACH transmission to higher layers (SIB5&6)
Company Confidential36 © Nokia Siemens Networks
RRC Connection Establishment UE-RAN
• Some of the early UEs are not capable of performing Open Loop PC accurately i.e. they have problems in RRC Connection Establishment
• The UE can not detect the SIB7 UL interference level correctly or cannot measure the CPICH RSCP accurately enough
• The situation can be corrected by increasing the parameter value PRACH_preamble_retrans or RACH_tx_Max
• Increasing the parameter values should be made with extra care as increasing the maximum UE TX power on RACH increases the UL load is as well:
• In case of problematic site which does not answer to PRACH at all due to BTS problems; increasing the power on RACH increases the UL interference on the surrounding sites
Company Confidential37 © Nokia Siemens Networks
Main RAN_Parameter Grouping
• Idle Mode: Cell Selection/ Re-selection
• RRC Connection Establishment
• RAB Establishment
• Handovers
Company Confidential38 © Nokia Siemens Networks
RADIO RESOURCE INDICATION (RRI) messagePrx Total is reported to the RNC for LC, AC and PS usage, on every RRIindicationperiod (200 ms)
The BTS is measuring:Prx Total
BTS sends the LASTEST averaged measurement result to RNC every RRI period
RNC is calculating a sliding window averaged value over the values given by RRI messagesFrame
measurements
Prx
…
RRIxRRIx+1RRIx+2 RRIx+n
Sliding window average result on every RRI periodWinAcRabSetup
UI(5)
m
jjntotalrx Totalx
mP
1
_ _Pr1
BTS uses ALPHA TRIMMED MEAN FILTERPrxAlpha (0)PrxMeasAvWindow
RAB Establishment
Company Confidential39 © Nokia Siemens Networks
• Parameters to change in order to decrease the AC rejection of RAB (or RRC) connection due to the UL interference exceeding PrxTarget (PrxTraget (4dB)+ PrxOffset(1dB))
• Each BTS measures the total received interference power (PrxTotal)
• BTS uses Alpha Trimmed Averaging Window to calculate Prx_Total values
• BTS reports the PrxTotal results to the RNC by using RADIO RESOURCE INDICATION message every RRIndPeriod (200ms)
• RNC calculates simple arithmetic mean to obtain averaged PrxTotal values
• WinAcRabSetupUl (5) is a BTS parameter that defines the size of the load measurement averaging window used in RNC (AC) to average PrxTotal results
• Sliding averaging window provides new av PrxTotal value every RRI period
RAB Establishment
Company Confidential42 © Nokia Siemens Networks
BTS sends periodically the received UL power to the RNCBTS sends periodically the received UL power to the RNC
Fractional load[0..1]
OVERLOADAREA
MARGINALLOADAREA
FEASIBLELOADAREA
0
Load curve in UL
PrxTotal[dBm]
PrxNoise [dBm]
PrxTarget [dB]
PrxTarget [dB]+PrxOffset [dB]
1
Noise RiseNR [dB]
XX [dB]
RNC compares the measured received power levels against the set thresholdsRNC compares the measured received power levels against the set thresholds
If measured UL (PrxTotal) load exceeds target thresholds (PrxTarget) AC may admit RT RABs and can admit NRT RABs to the cell. The NRT RAB bitrate can not be increased and remains at the same level as after previous scheduling period
If measured UL (PrxTotal) load exceeds overload thresholds (PrxTarget+PrxOffset) no RABs can be admitted and NRT bitrates are reduced until PrxTotal reaches again PrxTarget
Over Load
MarginalLoad
FeasibleLoad
In feasible load area the admission decision is based on the power rise estimate of the new RT bearer
If the resulting power is still below PrxTraget the RAB is admitted
rx_targetrx_ncrx_nc PPP
Uplink Admission Procedure
Company Confidential45 © Nokia Siemens Networks
BTS sends periodically the total transmitted DL power to the RNCBTS sends periodically the total transmitted DL power to the RNC
RNC compares the measured transmitted power levels against the thresholdsRNC compares the measured transmitted power levels against the thresholds
If measured DL (PtxTotal) transmitted power exceeds target thresholds (PtxTarget) AC may admit RT RABs and can admit NRT RABs to the cell.The NRT RAB bitrates can not be increased and they remain at the same level as after previous scheduling period
If measured DL (PTxTotal) transmitted power exceeds overload thresholds (PtxTarget+PtxOffset) no RABs can be admitted and NRT bitrates are reduced until PtxTotal reaches again PtxTarget
Over Load
MarginalLoad
FeasibleLoad
In feasible load area the admission decision is based on the power rise estimate of the new RT bearer
If the resulting power is still below PtxTraget the RAB is admitted
OVERLOADAREA
MARGINALLOADAREA
FEASIBLELOADAREA
Load curve in DL
PtxTotal[dBm]
PtxTarget [dBm]
PtxTarget [dBm]+PtxOffset [dB]
Cell maximum [dBm]
Load[0...1]
0 1
tx_targettxtx_total PPP
Downlink Admission Procedure
Company Confidential46 © Nokia Siemens Networks
Main RAN_Parameter Grouping
• Idle Mode: Cell Selection/ Re-selection
• RRC Connection Establishment
• RAB Establishment
• Handover
Company Confidential47 © Nokia Siemens Networks
Handover Types
Intra-Frequency Handover
SOFTER HANDOVERMS simultaneously connected to multiple cells (handled by same BTS)No extra transmissions across Iub interfaceMobile Evaluated HandOver (MEHO)Both UL and DL: Maximum Ratio Combining (MRC) is occurring in rake receiver
SOFT HANDOVER MS simultaneously connected to multiple cells (from different BTSs)Extra transmission across Iub, more channel cards are neededMobile Evaluated HandOver (MEHO)DL/UE: MRC UL/RNC: Frame selection combining
HARD HANDOVERArises when inter-RNC SHO is not possible (Iur not supported or Iur congestion)Decision procedure is the same as SHO (MEHO)Causes temporary disconnection
Inter-Frequency Handover
Can be intra-BS, intra-RNC, inter-RNC Network Evaluated HandOver (NEHO)
Inter-RAT (Inter-system) Handover
Handovers between GSM and WCDMA (NEHO)
Company Confidential48 © Nokia Siemens Networks
Handover Control Parameter Database Structure
RNC = Radio Network Controller level parameters
WBTS = Node B level parameters
WCELL = Cell level parameters
FMCx = Frequency Measurement Control parameters (S=intra-frequency set; I=inter-frequency; G=inter-RAT)
ADJx = Adjacent Cell parameters (S=intra-frequency set; I=inter-frequency; G=inter-RAT)
HOPx = Handover Path parameters (S=intra- frequency set; I=inter-frequency; G=inter-RAT)
RNCRNC
WBTSWBTS
WCELWCELADJSADJS
HOPSHOPS
ADJG
HOPG
FMCG ADJG
HOPG
FMCG
ADJI
HOPI
FMCI ADJI
HOPI
FMCIFMCI
FMCS
Company Confidential49 © Nokia Siemens Networks
ADJS
ADJS
FMCS(NRT)
FMCS(RT)
HOPS(RT)
HOPS(NRT)
NrtHopsIdentifier = 1
RtHopsIdentifier = 2
HSDPAHopsIdentifier = 6
NrtHopsIdentifier = 1
RtHopsIdentifier = 2
HSDPAHopsIdentifier = 6 HOPSid = 1
HOPSid = 2
FMCSid = 1
FMCSid = 1
ADJSid = 1
ADJSid = 2
WCEL
WCEL
WCELWBTS
Each WCEL has associated 1 FMCS for NRT & 1 for RT & 2 for HSDPA, all can be reused for other cells.
Each ADJS has associated 1 HOPS for NRT & 1 for RT & 1 for HSDPA, sets can be reused for other cells.)
NrtFmcsIdentifier = 3
RtFmcsIdentifier = 40
HSDPAFmcsIdentifier = 50
NrtFmcsIdentifier = 3
RtFmcsIdentifier = 40
HSDPAFmcsIdentifier = 50
FMCS(HSDPA)
FMCSid = 2
HOPS(HSDPA) HOPSid = 6
HOPS(RT)
HOPS(NRT)
HOPSid = 1
HOPSid = 5
HOPS(HSDPA) HOPSid = 7
FMCS(RT&HSDPA)
FMCSid = 2
Handover Control Parameters Summary
Company Confidential50 © Nokia Siemens Networks
Soft Handover
HC supports the following measurement reporting events and features:
• Event 1A: A primary CPICH enters the reporting range (Ncell addition)
• Event 1B: A primary CPICH leaves the reporting range (Ncell deletion)
• Event 1C: A non-active CPICH becomes better than an active primary CPICH (Ncell replacement)
• Cell individual offsets for modifying measurement reporting behaviour
• Mechanism for forbidding a neighbouring cell to affect the reporting range
Handover decision performed by RNC based on measurements and available resources
Admission Control can reject the branch addition in case the maximum load is achieved in DL (threshold + offset), valid both for RT and NRT bitrates.
Hard blocking may prevent branch addition
Company Confidential52 © Nokia Siemens Networks
1A: A Primary CPICH Enters the Reporting Range
Reporting range defined by offset (point 1 on next slide) from either
(i) best CPICH Ec/Io in the AS, or(ii) sum of the AS measurement resultsset using ActiveSetWeightingCoefficient(0) (FMCS) (0 = use best CPICH : <>0 = use sum)
Offset defined using AdditionWindow (4/RT & 2.5 NRT) (FMCS)
Event 1A triggered when CPCIH3 Ec/Io enters UE reporting range (point 2)
If CPICH3 Ec/Io remains within reporting range for a time period defined by AdditionTime (FMCS) , and the AS is not full, UE sends measurement report to RNC which adds Ncell3 to AS if possible (point 3)
AdditionTime (320ms) defines the 'time-to-trigger' interval between the Ncell first entering the reporting range and the UE sending the measurement report to the RNC
If RNC is unable to add Ncell to AS, UE will wait for a period of time, defined by AdditionReportingInterval (0.5) (FMCS) (point 4) after the first measurement report, before sending further reports periodically, with interval AdditionReportingInterval, until (a) Ncell moves out of reporting range, or (b) RNC adds Ncell to AS.
2
3
1
4
Company Confidential53 © Nokia Siemens Networks
1A: A Primary CPICH Enters the Reporting Range
Strongest CPICH in AS
time
Ec/No
P CPICH 3
P CPICH 1
P CPICH 2
1
2
AdditionWindow
AdditionTime
AdditionReportingInterval
RNC
MeasurementReport
Add tothe AS?
no
ActiveSetWeightingCoefficient
34
Company Confidential55 © Nokia Siemens Networks
1B: A Primary CPICH Leaves the Reporting Range
Event 1B triggered when CPICH3 EC/I0 drops out of the UE reporting range for a defined period of time (point 1 on next slide)
Reporting range = Strongest CPICH in AS – DropWindow (6/RT & 8/NRT) (FMCS) (point 2)
Time-to-trigger period set using DropTime (640ms) (FMCS) (point 3)
UE sends RNC measurement report on expiry of DropTime to remove Ncell (CPICH3) from AS.
RNC drops the cell from the AS and UE drops the cell from the AS to the Neighbour Set
1
2
3
Company Confidential56 © Nokia Siemens Networks
Strongest CPICH in AS
time
Ec/No
P CPICH 3
P CPICH 1
P CPICH 2
1
2
3
DropWindow
DropTime
MeasurementReport
1B: A Primary CPICH leaves the Reporting Range
Remove the
reported cell from the AS
Company Confidential58 © Nokia Siemens Networks
1C: A non-active CPICH becomes better than an active primary CPICH
UE AS full (MaxActiveSetSize = 3)
Event 1C triggered when CPICH4 EC/IO > CPICH3 in AS by a defined margin, ReplacementWindow (2 dB) (FMCS). (point 1 in next slide)
Sending of measurement report to RNC can be delayed by using 'time-to-trigger' period set by ReplacementTime (320ms) (FMCS)
If 'time-to-trigger' is used difference between CPICH4 and CPICH3 must be ReplacementWindow for the period of ReplacementTime (point 2)
If the RNC is not able to replace the Ncells, the UE continues to send measurement reports periodically, with interval ReplacementReportingInterval (0.5S), to the RNC until (a) CPICH4 falls out of ReplacementWindow or (b) RNC replaces CPICH4 by CPICH3 (point 3)
3
1
2
Company Confidential59 © Nokia Siemens Networks
time
weakest CPICH3 in AS
Ec/No
P CPICH 3
P CPICH 1
P CPICH 2
P CPICH 4
AS has 3 cells
ReplacementReportingInterval3
1
2
ReplacementWindow
ReplacementTime
MeasurementReport
RNC
ASupdate?
no
1C: A non-active CPICH becomes better than an active primary CPICH
Company Confidential62 © Nokia Siemens Networks
Inter-RNC Soft HO
Inter-RNC soft Handovers are performed if:
• RNC Iur list: IurUPSupport (1) indicates whether nighbouring RNC supports user plane over Iur, thus if it’s possible to initiate inter-RNC SHO procedure
• HOPS: EnableInterRNCsho (1) indicates whether adjacent cell can participate in a inter-RNC SHO
EnableInterRNCsho
cell3 cell2
cell1
cell4
cell6
cell5
RNC RNCIurUPSupport
EnableInterRNCsho
Otherwise, HC checks whether Hard Handover is possible.
(UE-involved SRNS relocation is needed)
Company Confidential63 © Nokia Siemens Networks
Hard Handover (1/3)
If RNC is not able to add (Event 1A) to or replace (Event 1C) an Ncell from the AS, UE sends periodic measurement reports (AdditionReportingInterval / ReplacementReportingInterval) until;
Ncell is added/replaced in to AS
Ncell leaves reporting range
HO no longer required (e.g. different Ncell enters AS)
RNC may not be able to add/replace Ncell due to (a) Iur congestion or (b) inter-RNC SHO is prevented due to setting of EnableInterRNCsho (HOPS) (Point 1 in next slide)
If CPICH EC/NO of non-active Ncell continues to increase it will cause additional interference due to a non-optimal connection (point 2)
1
2
Company Confidential64 © Nokia Siemens Networks
Hard Handover (2/3)
To avoid excessive uplink interference, RNC will perform an intra-frequency hard Handover if either of the following criteria are met
AveEcNoDownlink + HHoMarginForAveEcNo(1dB)(n) < AvEcNoNcell(n)
EcNoDownlink + HHoMarginPeakEcNo(2dB)(n) < EcNoNcell(n)
AveEcNoDownlink and AvEcNoNcell(n) = measured values for the best AS cell and the nth NS cell, averaged over EcNoAveragingWindow (8dB) measurements
EcNoDownlink and EcNoNcell(n) = instantaneous values
HHoMarginForAveEcNo (HOPS) = average Ec/N0 margin [-6 … 6]dB, default 1dB
HHOMarginPeakEcNo (HOPS) = peak Ec/N0 margin [-6 … 6]dB, default 2dB
3
Company Confidential65 © Nokia Siemens Networks
Time
Ec/No
P CPICH 3
P CPICH 1
P CPICH 2Reporting
range
AdditionReportingInterval
1
2
HHOMarginAverageEcNoHHOMarginPeakEcNo
1A (AdditionTime = 0)
AveEcNoDownlink + HHOMarginAveEcNo < AveEcNoNcellEcNoDownlink + HHOMarginPeakEcNo < EcNONcell
Hard Handover (3/3)
3
Company Confidential66 © Nokia Siemens Networks
If difference between the best AS cell and the NS cell is too high and SHO is not performed, the RRC connection is released to avoid excessive interference
Why might an AS update not be possible?• Excessive load in the neighboring cell
• Hard blocking in the target BTS
• Unavailability of DL spreading codes
• Iub transport resources unavailable
This function is activated by EnableRRCRelease (0) (HOPS parameter)/0=no (def),1 =yes
The RRC connection is released if either:
AveEcNoDownlink + ReleaseMarginForAveEcNo (2.5dB)(n) < AvEcNoNcell(n)
EcNoDownlink + ReleaseMarginPeakEcNo(3.5)(n) < EcNoNcell(n)
ReleaseMarginForAveEcNo (HOPS) = average Eb/N0 margin [-6 … 6] dB, default 2.5dB
ReleaseMarginPeakEcNo (HOPS) = peak Eb/N0 margin [-6 … 6] dB, default 3.5dB
Emergency calls are exempt from RRC Connection Release process.
RRC Connection Release
Company Confidential67 © Nokia Siemens Networks
HO Triggering Thresholds set in RNCHO Triggering Thresholds set in RNC
Event Triggered Coverage/Capacitybased HO fulfilled in RNC
Event Triggered Coverage/Capacitybased HO fulfilled in RNC
RNC commands selected UE(s) to startIF/IS measurements
RNC commands selected UE(s) to startIF/IS measurements
Measurements are done in Compressed Mode (CM)
Measurements are done in Compressed Mode (CM)
UE reports GSM cells withstrongest RSSI signals to RNC
UE reports GSM cells withstrongest RSSI signals to RNC
RNC makes HO decision andcommands UE to target cell
RNC makes HO decision andcommands UE to target cell
RSSI measurements and BSICverification for GSM cells
RSSI measurements and BSICverification for GSM cells
Different decision methods for IF HOOnly one decision method for IS HO
5 Coverage/Capacity HO Reasons
About 25 HO parameters
Reporting cells are active set cells (max 3) + max 6 IFHO, max 6 ISHO neighb.
Max 32 neighbours could be measured
(31 Intra-Freq neighbours)48 Inter-Freq neighbours 32 Inter-System neighbours can be measured
3G->2G Handover Process
Company Confidential68 © Nokia Siemens Networks
1. DL DPCH approaches itsmaximum allowed powerFMCG: GSMcauseTxPwrDL
2. Quality deterioration report from UL outer loop PCFMCG: GSMcauseUplinkQuality
4. UE Tx power approaches itsmaximum allowed power, event 6A/6DFMCG: GSMcauseTxPwrUL
5 . Low measured absoluteCPICH RSCP, events 1E/1FFMCG: GSMcauseCPICHrscp
3. Low measured absolute CPICH Ec/No, event 1E/1F FMCG: GSMcauseCPICHEcNo
HO trigger
6 . Others e.g. Traffic & load reason IS-HO, etc
Frequency Measuring Control for Inter-System (GSM) = FMCG
3G->2G ISHO Trigerring Reason
Company Confidential70 © Nokia Siemens Networks
Measurement trigger CPICH Ec/No (1/3)
Reporting event: 1E: A P-CPICH exceeds an absolute threshold 1F: A P-CPICH falls below an absolute threshold (HO triggered if
all)
time
Cell 1 Cell 2
Cell 3
absolutethreshold
e.g
. P
-CP
ICH
Ec/N
o
1E: HHoEcNoCancel (-9dB)
1E: HHoEcNoCancelTime (100ms)
1F: HHoEcNoThreshold(-12dB)
1F: HHoEcNoTimeHysteresis (100ms)
Company Confidential71 © Nokia Siemens Networks
Measurement trigger CPICH Ec/No (2/3)
RNC starts IF/IS measurement when event 1F occurs for all cells in the active set: A Primary CPICH becomes less than an absolute threshold
RNC stops IF/IS measurement when event 1E occurs for at least one cell of the active set : A Primary CPICH becomes better than an absolute threshold
Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events 1E only when IFHO/ISHO was not successful and only inside the time between CM measurements, specified by the time InterFreqMinMeasInterval(6s) GsmMinMeasInterval(2s)/default 10s, recommendation 2s.
Filtering applied before event evaluation in the UE:
FMCS: EcNoFilterCoefficient/0= 200ms filtering period (600ms)
Company Confidential72 © Nokia Siemens Networks
Measurement trigger CPICH Ec/No (3/3)
Event 1E parameters:Triggering conditions: Active set cells
Hysteresis: not used in 1F
Threshold used frequency: FMCS : HHoEcNoCancel(-9)/ -20 dB
Time-to-trigger: FMCS: HHoEcNoCancelTime (100ms)/ 1280 ms
Amount of reporting: infinity
Reporting interval: not applied
Reporting cell status: max 3 active cells
Event 1F parameters:Triggering conditions: Active set cells
hysteresis: not used in 1F
Threshold used frequency: FMCS : HHoEcNoThreshold (-12)/ - 22 dB (range 0..-24 dB)
Time-to-trigger: FMCS: HHoEcNoTimeHysteresis(100ms) / 640 ms (range 0..5000ms)
Amount of reporting: infinity
Reporting interval: not applied
Reporting cell status: max 3 active cells
Company Confidential73 © Nokia Siemens Networks
Measurement trigger CPICH RSCP (1/2)
UE continually monitors pilot channels of BTSs in AS.
If RSCP of a Node B falls below threshold, HHoRscpThreshold (105dbm), UE sends event 1F report.
RNC starts IF/IS measurements when event 1F occurs for all cells in AS.
RNC stops IF/IS measurements when event 1E occurs for at least one cell of AS.
Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events 1E only when IFHO/ISHO was not successful and only inside the time between CM measurements, specified by the time InterFreqMinMeasInterval(6s) GsmMinMeasInterval(2s)/default 10s, recommendation 2s.
UE filtering applied before event evaluation using HHoRscpFilterCoefficient (200ms) (FMCS) /200ms, range 200…1600ms
Company Confidential74 © Nokia Siemens Networks
Measurement trigger CPICH RSCP (2/2)Event 1E (A primary CPICH exceeds an absolute threshold) parameters:
Triggering conditions: Active set cellshysteresis: not used in 1EThreshold used frequency: (FMCS) : HHoRscpCancel(-102dBm)/ - 100 dBmTime-to-trigger: (FMCS): HHoRscpCancelTime(100ms)/ 1280 msAmount of reporting: infinityReporting interval: not appliedReporting cell status: max 3 active cells
Event 1F (A primary CPICH falls below an absolute threshold) parameters:Triggering conditions: Active set cells
Hysteresis: not used in 1F
Threshold used frequency: HHoRscpThreshold RT (-12dB)/NRT (-15dB)(FMCS)/ - 105 dBm
Time-to-trigger: HHoRscpTimeHysteresis (-100ms)(FMCS)/ 640 ms
Amount of reporting: infinity
Reporting interval: not applied
Reporting cell status: max 3 active cells
Company Confidential75 © Nokia Siemens Networks
Decision Algorithm
UE Tx Power (Event 6A)•Threshold:GsmUETxPwrThrXX •L3 filter: GsmUETxPwrFilterCoeff•Hysteresis margin: GsmUETxPwrTimeHyst•Data rate threshold HHOMAxAllowedBitrateUL
UL Quality•Timer:ULQualDetRepThreshold•Data rate threshold HHOMAxAllowedBitrateUL
DL DPCH power•Threshold: GsmDLTxPwrThrXX•Data rate threshold HHOMAxAllowedBitrateDL
(XX=AMR,CS,NrtPS,RtPS)
CPICH RSCP (Event 1F)
•Thresholds:HHoRscpThreshold HHoRscpCancelL3 filter: HHoRscpFilterCoefficient•Timers:HHoRscpTimeHysteresisHHoRscpCancelTime
CPICH Ec/Io (Event 1F)•Thresholds:HHoEcNoThresholdHHoEcNoCancel•L3 filter:Done already for SHO•Timers:HHoEcNoTimeHysteresisHHoEcNoCancelTime
AdjgTxPwrMaxTCHAdjgRxLevMinHO (n)GsmMeasAveWindow
GsmMeasRepIntervalGsmNcellSearchPeriodGsmMinMeasIntervalGsmMaxMeasPeriod
Handover Triggering
Handover Execution2G-to-3G back prevention
GsmMinHoInterval
GSM measurement reporting
ISHO Summary Parameters
Company Confidential76 © Nokia Siemens Networks
Handover Triggering Thresholds set in BSCHandover Triggering Thresholds set in BSC
Inter-RAT measurements when: The RXLEV of the serving cell is above or
below the given threshold Qsearch_C
Inter-RAT measurements when: The RXLEV of the serving cell is above or
below the given threshold Qsearch_C
Handover Decision is done in case of• Load of the serving cell > Load_Threshold• and CPICH Ec/No> min Ec/No Threshold
Handover Decision is done in case of• Load of the serving cell > Load_Threshold• and CPICH Ec/No> min Ec/No Threshold
MS reports best UTRAN cell based on measurement results
MS reports best UTRAN cell based on measurement results
Handover command is send to MSCHandover command is send to MSC
Latest after 5 s(one WCDMA band)
MS is measuring the UTRAN cells continuously if they are defined as a neighbour, measurements are done during idle periods
2G->3G Handover Process
Company Confidential77 © Nokia Siemens Networks
2G->3G ISHO Parameters
Company Confidential83 © Nokia Siemens Networks
• The following conditions have to be satisfied, before an inter-system Handover can be conducted. The best neighboring cell must fulfil following criterion („best“ according to Ec/No):
AVE_RXLEV_NCell(n) > AdjgRxLevMinHO(-95dBm)(n) + max(0, AdjgTxPwrMaxTCH(n) - P_max)where:
• AVE_RXLEV _Ncell(n) is the averaged GSM carrier RSSI value of the GSM neighbor cell(n), averaging done directly from dBm values (no linear averaging) -> GSMMeasAveWindow(6) / 6, 1…32 meas report
• AdjgRxLevMinHO(-95dBm)(n) determines the minimum Required RSSI (dBm) level of the neighbor cell(n).
• AdjgTxPwrMaxTCH(30dBm for1800Mhz/33dBm 900Mhz)(n) indicated the maximum Tx power level (dBm) an UE may use in GSM neighbor cell(n).
• P_MAX is the maximum UE power capability.• If several GSM cells fulfil the equation above, cells are ranked based on HOPG:
AdjgPriorityCoverage(0)/0, range 0…7• A cell is ranked higher than another cell if it has a higher priority level
even though its signal strength condition was worse• Inter-system HO could be forbidden during the first measurements reports from
the UE, to let the UE report all the candidate inter-system cells in its neighbor hood.
• FMCG NcellSearchPeriod (0)/ 0
ISHO Decision (1/2)
Company Confidential84 © Nokia Siemens Networks
AdjgRxLevMinHO(n)
max(0, AdjgTxPwrMaxTCH(n) - P_max)
AVE_RXLEV_NCell(n) > AdjgRxLevMinHO(n) + max(0, AdjgTxPwrMaxTCH(n) - P_max)
GSM cell
ISHO Decision (2/2)
Company Confidential85 © Nokia Siemens Networks
Compressed Mode (CM)
CM was introduced to WCDMA to allow inter-frequency (system) Handovers
CM is used to create idle periods (gaps) in the transmission during which ncell measurements on another frequency can be made
Gaps can be created using single or double frame approach (Nokia supports both)
Because same data amount is sent in a shorter time more power is needed during CM (both in UE and BTS)
=> affects WCDMA coverage
Fast Power control information might be lost during the gap => higher Eb/No
=> affects WCDMA capacity
Compressed frames may be lost if power control is not set correctly
=> affects WCDMA quality
CM methods are Spreading Factor Halving and Higher Layer Scheduling
Normal frame Normal frame
Measurement gapMeasurement gapPower / Data Rate
CompressedMode
Normal frame
Company Confidential87 © Nokia Siemens Networks
Compressed Mode Parameters
CM can be activated/deactivated by CMmasterSwitch (RNC)(0) /0=in use (def)
Maximum number of UEs in CM is controlled through MaxNumbUECMcoverHO (RNC)(16)/16 (range 0..255)
The number of UEs in DL CM depends on the PtxTotal value
The number of UEs in UL CM depends on the PrxTotal value
Company Confidential88 © Nokia Siemens Networks
How many UEs in Compressed Mode ?
PtxTarget/PrxTarget
DL/ULtransmission power
Load
PtxOffset/PrxOffset
New UEs can be switched to CM when:
Pxx_Total < Pxx_Target & # of UEs in CM <
MaxNumbUECMcoverHO
One new UE in CM can be allowed
if the limit is not reached
No new UE can be in CM here
Company Confidential89 © Nokia Siemens Networks
Specific HSDPA Parameter
Company Confidential90 © Nokia Siemens Networks
User plane Iub capacity allocation
• The user plane Iub capacity is shared by the R99 and HSDPA traffic.
• The HSDPA Iub resource allocation is managed with parameters:
SharedHSDPAAllocation (WBTS object) (1.3Mbps 2E1 & 2 Mbps 3E1)
• capacity reservation from the user plane VCC for HSDPA
NbrOfOverbookedHSDPAUsers (WBTS object) (32)
• determines the number of HSDPA users that are allowed in the VCC even if the SharedHSDPAAllocation has failed
ReleaseTimerForSharedHSDPAallocation (WBTS object) (3 minutes)
• timer that keeps SharedHSDPAAllocation reservation after the last HSDPA user has left
SharedHSDPAFlowControlAllocation (WBTS object) (4Mbps 2E1, 4.8Mbps (3E1)
• sets an upper limit to the allowed HSDPA bandwidth
Company Confidential91 © Nokia Siemens Networks
Time
VCC capacity
R99 DCH rate
Available Iub bandwidth for the HSDPA traffic
Shared HSDPAallocation
Initially, the R99 traffic can use the whole VCC capacity.
If the HSDPA user enters at t0, SharedHSDPAAllocationSharedHSDPAAllocation reservation is not possible due to DCH usage.
Then the Iub reservation gives to HSDPA all what is available at t0 (best effort).
t0
Company Confidential92 © Nokia Siemens Networks
Time
VCC capacity
R99 DCH rate
Available Iub bandwidth for the HSDPA traffic
Let’s assume now that at t1 another HSDPA user tries to enter the system.
Again, SharedHSDPAAllocationSharedHSDPAAllocation reservation fails due to DCH usage.Then, its admission depends on the parameter
NbrOfOverbookedHSDPAUsers:NbrOfOverbookedHSDPAUsers:
If =1, the user at t1 is rejectedIf > 1, the user at t1 is admittedIf = 0, the user at t1 is admitted as the feature is disabled with value
0
At t2 a third user tries to enter and the capacity allocation is the SharedHSDPAallocationSharedHSDPAallocation
t0 t1 t2
Shared HSDPAallocation
Company Confidential93 © Nokia Siemens Networks
R99 DCH rate
Time
VCC capacityPeak R99 DCH rate
AvailabAvailable le
bandwibandwidth fordth forHSDPAHSDPA
VCC Capacity- R99 DCH peak rate
VCC capacity
Peak R99 DCH rate < VCC capacity
Peak R99 DCH rate < VCC capacity
Available bandwidth for the HSDPA traffic SharedHSDPAallocation
If reservation succeeds, the bandwidth reserved to HSDPA is equal to SharedHSDPAallocation (if reservation has succeeded). This is flow level capacity, on packet level each packet is transmitted with the full capacity of the virtual connection.
SharedHSDPAallocation a.k.a “Dummy reservation” as this is capacity hidden from the CAC.
This reservation is maintained as long as there are active HSDPA users in the BTS. When the last MAC-d terminates and no new ones enter during a period determined by [WBTS] Release timer for shared HSDPA allocationRelease timer for shared HSDPA allocation, the capacity reservation is released. This means that the whole of the Iub capacity is again available for DCH usage.
Shared HSDPAallocation
Company Confidential94 © Nokia Siemens Networks
Time
VCC capacity
R99 DCH rate
Maximum bandwidth for the HSDPA traffic SharedHSDPAFlowControlAllocation
It is possible to send MAC-d flow data over Iub faster than what is reserved for HSDPA.
Shared HSDPA flow control allocationShared HSDPA flow control allocation controls the maximum share of Iub that HSDPA can try to use.
Range 500 kbps … 14.4 Mbps in 100 k steps Should be bigger than SharedHSDPAallocation.
SharedHSDPAFlowControlAllocation
Shared HSDPAallocation
Company Confidential95 © Nokia Siemens Networks
Iub HSDPA allocation
When the capacity reservation for HSDPA traffic in the Iub interface is activated, the reservation is made when the first MAC-d flow enters the Iub.
The transport capacity reserved for HSDPA is always available for MAC-d flows over Iub regardless of the load.
The ShareHSDPAAllocation reservation will fail if there is no capacity available due to DCH usage.
If this happens, the HSDPA data is transported as best effort traffic without reservation and is therefore subject to buffering depending on the current DCH load.
In this case, the HSDPA data is able to utilize only the capacity which is left over from the DCH traffic. Every time a new MAC-d flow enters the Iub, the retry for ShareHSDPAAllocation reservation is made.
If the reservation succeeds, Shared HSDPA allocation Shared HSDPA allocation is a virtual AAL2 reservation inside the shared VCC. The reserved capacity is for all MAC-d flows on route, and not done for any specific MAC-d flow. In other words, some transport resources are reserved from VCC towards BTS, but no AAL2 connection is established over Iub. Therefore, the reservation of shared HSDPA transport resources in RNC is not visible to BTS.
Company Confidential96 © Nokia Siemens Networks
Power Allocation
• HSDPAPriority (RNC object) (1)• Defines priority between NRT DCHs and MAC-d flows.• should be in line with strategy.
• PtxTargetHSDPA (WCEL object) (38.5 dBm)• Used instead of PtxTraget.• Default, 38.5 dBm• Should be in-line with PtxMaxHSDPA
• PtxOffsetHSDPA (WCEL object) (0.8)• Used instead of PtxOffset.• Default, 0.8 dB• Should be in-line with PtxMaxHSDPA
• PtxMaxHSDPA (WCEL object) (37.8 dBm)• Defines maximum HSDPA transmission power.• should be in-line with strategy
Company Confidential97 © Nokia Siemens Networks
Power allocation
Max power
Node-B Tx power
HSDPAPriority =1
• Event A: First MAC-d flow entering the cell
PtxNC<=PtxtargetHSDPA-> HS-DSCH is selected,
otherwise DCH scheduling.• When HSDPA power is in use:
PtxNC target is Ptxtarget. NRT DCH scheduling up to PtxtargetHSDPA.
• Event B:PtxnonHSDPA>=PtxtargetHSDPA+Ptxoffset
HSPA- Overload control actions for NRT DCH(s) started
• Event C:PtxnonHSDPA>=PtxtargetHSDPA+Ptxoffset
HSDPA- No more NRT DCHs, all MAC-d flows in the cell are released A
Ptx_offset_HSDPAPtxnonHSDPA
PtxNC
Ptx_target_HSDPA
B
Ptxtotal
Ptx_target
C
PtxMaxHSDPA
Company Confidential98 © Nokia Siemens Networks
Power allocation
HSDPAPriority =2
• Event A: First MAC-d flow entering the cell
Ptxtotal<=PtxtargetHSDPA-> HS-DSCH is selected,
otherwise DCH scheduling.• When HSDPA power is in
use: PtxNC target is Ptxtarget. NRT DCH scheduling up to PtxtargetHSDPA.
• Event B:PtxnonHSDPA>=PtxtargetHSDPA+Ptxoffset
HSDA- All MAC-d flows in the cell released
• Event C: (normal NRT DCH overload control)
Ptxtotal>=Ptxtarget+Ptxoffset- Overload control actions for NRT DCH(s) started A B C
Max power
Node-B Tx power
Ptx_offset_HSDPA
PtxnonHSDPA
PtxNC
Ptx_target_HSDPA
Ptxtotal
Ptx_target
Ptx_offset
PtxMaxHSDPA
Company Confidential99 © Nokia Siemens Networks
PtxtargetHSDPA AND PtxoffsetHSDPA
STRATEGY: STRATEGY: 1) The ratio between PC headroom and Variable Power shall remain the same 1) The ratio between PC headroom and Variable Power shall remain the same after the after the introduction of HSDPA because HSDPA does not require any power control introduction of HSDPA because HSDPA does not require any power control headroomheadroom2) When HSDPA power is allocated DCH Power increases to to keep BLER targets, 2) When HSDPA power is allocated DCH Power increases to to keep BLER targets, so in order to avoid HSDPA power to be allocated and soon released DCH power so in order to avoid HSDPA power to be allocated and soon released DCH power increase << PtxoffsetHSDPAincrease << PtxoffsetHSDPA
Company Confidential100 © Nokia Siemens Networks
HS-DSCH Release
• MACdflowutilRelThr (256bps) (RNC object)• Defines the low utilization threshold of the throughput
measurement of the MAC-d flow.• Default 256 bps.
• MACdflowutilTimetoTrigger (0s) (RNC object)• Defines the low utilization time to trigger timer• Default, 0s.
• MACdflowthrouhgputRelThr(0bps) (RNC object)• Defines the low throughput threshold of the throughput
measurement of the MAC-d flow.• Default 0 bps.
• MACdflowthroughputTimetoTrigger(5s) (RNC object)• Defines the low throughput time to trigger timer• Default, 5s
• HsdschGuardTimeLowThroughput(30s) (RNC object)• Defines time when HS-DSCH allocation is not allowed for a UE,
after the MAC-d flow is release due to low throughput.
Company Confidential101 © Nokia Siemens Networks
HS-DSCH & MAC-d release: low utilization
Throughput
PDUs in buffer
MACdflowUtilRelThr
MACdflowthrougputRelThr
MACdflowUtilTimetoTrigger
Low utilization indication
Company Confidential102 © Nokia Siemens Networks
HS-DSCH & MAC-d release : low throughput
Throughput
PDUs in buffer
MACdflowUtilRelThr
MACdflowthrougputRelThr
MACdflowUtilTimetoTrigger
Low throughput indication
MACdflowThroughputTimetoTrigger
HsdschGuardTimerLowThroughput, def. 30s
Company Confidential103 © Nokia Siemens Networks
HS-DSCH & MAC-d release
UE moved to Cell FACH
L3 starts procedure to release UL NRT DCH and MAC-d flow if:• MAC-d flow has low utilization and UL NRT DCH can be released
(InactivityTimer).
Or • MAC-d flow has low throughput and UL NRT DCH can be released
(InactivityTimer). In this case UE specific timer HsdschGuardTimerLowThroughput is started.
If MAC-d flow has both low utilization and low throughput conditions valid at the same time, the functionality described in case of low utilization is followed
HS-DSCH & associated DCHs
released
Company Confidential104 © Nokia Siemens Networks