Power Control & Power Setting
Overview
Overview Objective Improve cell edge behaviour, reduce inter-cell interference and power consumption.
Downlink (DL) DL ‘Semi-static’ Power Setting • eN eNod odeB eB give gives s fixed power density per PRB scheduled for transport. – Total Tx powe powerr is max. when all all PRBs are scheduled scheduled – No adaptive/dynamic power control – (O&M parameter) Cell Power Reduction level CELL_PWR_RED [0...10] dB attenuation in 0.1 dB steps DL Power Control on PDCCH dlCellPwrRed
Uplink (UL) Slow Uplink Power Control • Combination of open loop PC and closed loop PC • Open Loop Power Control (OLPC) – Calculate Calculated d at the UE based on pathlo pathloss ss mea measurem surements ents • Closed Loop Power Control (CLPC) – Based on exchange of feedback data and commands between UE and eNodeB – SW-licensed enhancement (can be switched on and off)
Reduction of DL Tx power; deducted from max. antenna TX power. LNCEL; 0..10; 0.1; 0 dB
UL-PC: Overview UL-PC:
UL-PC: Overview LTE: orthogonal UL UL Tx, i.e. near-far-problem much less severe than WCDMA dynamic, slow PC PC – Open Loop (OL) (OL) & Closed Loop (CL (CL)) • UL: dynamic, • need for PL / shadowing etc. compensation OL PC • need for correction/ adjustments of e.g. open loop inaccuracies CL PC
Signal strength S: Depends on PL, indoor loss etc., i.e. location
Low
High
Interference (I) - main main cause: cause: inter-c inter-cell ell Noise (N) = kB T ∆f + NFeNB
Power control does not control the absolute UE Tx power but the Power Spectral Density (PSD), (PSD) , power per Hz, for a device. The PSDs at the eNodeB from different users have to be close to each other so the receiver doesn’t work over a large range of powers. Different data rates mean different Tx bandwidths so the absolute Tx power of the UE will also change. PC makes that the PSD is constant independently of the Tx bandwidth.
Overview Procedure for Slow UL Power Control • UE control controls s the Tx pow power er to keep keep the transmitted power spectral density (PSD) constant independent of the allocated transmit bandwidth (#PRBs)
• If no feedback feedback from eNodeB ( in the PDCCH UL UL PC command) the UE performs open open loop PC based on path loss measurements measurements
• If feedback feedback from eNode eNodeB B the UE correct corrects s the PSD when when receiving receiving PC command commands s from eNodeB eNodeB ( in the PDCCH UL PC command) command)
PC commands (up and down) based on UL quality and signal level measurements
• Applied separately for PUSCH, PUCCH • Scope of UL PC is UE level ( performed separately for each UE in a cell) 2) SINR measurment 3) Setting new power offset
4) TX power level adjustment with the new offset 1) Initial TX power level
UL-PC: PUSCH UL-PC:
UL-PC: PUSCH Equation PPUSCH (i) :PUSCH Power in subframe i Open Loop (OL)
Closed Loop (CL)
PPUSCH(i) = min {PCMAX ,10 log10 ( M PUSCH(i)) + PO_PUSCH( j) + ( j ) ⋅ PL + ∆TF (i) + f (i)} [dBm]
*PH = Power Headroom
UL-PC: PUSCH PPUSCH (i) = min {PCMAX ,10 log10 ( M PUSCH (i)) + PO_PUSCH( j ) + ( j ) ⋅ PL + ∆TF (i) + f (i)} [dBm] PH (i ) = PCMAX
−
10 log10 ( M PUSCH (i )) + PO_PUSCH ( j ) + α ⋅ PL + ∆ TF (i ) + f (i)
[dB]
PH = Power Headroom
PPUSCH (i) :PUSCH Power in subframe i PCMAX: max. allowed UE power (23 dBm for clas class s 3) MPUSCH: number of scheduled RBs (The UE Tx. Power increases proportionally to # of PRBs) PO_PUSCH(j) = PO_NOMINAL_PUSCH (j) + PO_UE_PUSCH(j)
PL: pat pathlo hloss ss [d [dB] B] = ref refere erence nceSig Signal nalPower Power – hig higher her lay layer er filt filtere ered d RSRP RSRP ∆TF
(i) = 10 log 10 ( 2MPR Ks – 1) for Ks = 1.25 else 0, MPR = TBS/N RE, NRE : number of RE
Ks defined by deltaMCS-Enabled , UE specific
f(i): TPC (Closed Loop adjustment)
j : This can be 0 or 1, j = 0, 1 come c ome from higher layer layer Semi-persistant: j=0 / dyn dynamic amic scheduling: j=1 PO_NOMINAL_PUSCH (0,1): cell specific (SysInfo) PO_UE_PUSCH(0,1): UE specific (RRC) α
(0,1) = 0.0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 (partial PL compensation by open loop)
Random access grant: j=2
Open Loop PC vs. Closed Loop PC Open Loop Power Control Target: provide a basic operating point for a suitable PSD for an average MCS (average SINR): Basic _ Operating _ Po int
=
PO_PUSCH ( j ) + α ( j ) ⋅ PL
• Open Loop Power Power Control takes into account effects like inter-cell interference and shadowing • Based on PL (Pathloss) Closed Loop Power Control f(i) adjustments Target: Fine tuning around the basic operating point • Adapt dynamically dynamically to the channel conditions (take into account e.g. fast fading) • Correct the estimations of power from the open loop PC ulpcEnable
Open Loop PC PPUSCH(i) = min {PCMAX,10 log10 ( M PUSCH(i)) + PO_PUSCH( j ) + ( j) ⋅ PL + ∆TF (i) + f (i)} [dBm]
PO_PUSCH(j) = PO_NOMINAL_PUSCH(j) + PO_UE_PUSCH(j) j=0 -> PUSCH transmission transmission with semi-persistent semi-persistent grant grant j=1 -> PUSCH transmission with dynamic scheduling j=2 -> PUSCH transmission for random access grant
PO_NOMINAL_PUSCH(j) -> cell specific component signaled from system information for j=0, 1 This term is a common power power level for all mobiles in i n the cell (used to control SINR) p0NomPusch Nominal Power for UE PUSCH Tx Power Calculation LNCEL; -126..24dbm; 1; -100 dBm PO_UE_PUSCH(j)
-> UE specific component provided by higher layers (RRC) for j=0,1 j= 0,1 This term is a UE specific offset used to correct the errors from the estimation of the pathloss
PUSCH Formula PPUSCH(i) = min {PCMAX ,10 log10 ( M PUSCH(i)) + PO_PUSCH( j) + ( j ) ⋅ PL + ∆TF (i) + f (i)} [dBm]
PL: pat pathlo hloss ss [d [dB] B] = ref referen erenceS ceSign ignalP alPower ower – higher layer filtered RSRP
This path loss compensation factor a is adjustable by
Alpha
O&M. α is a cell - specific specific parame parameter ter (broadca (broadcasted sted on BCH).
α ∈ [0.0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0]
ulpcAlpha LNCEL; 0, 0.4..1.0; 0.1; 1.0
α
= 0 , no compensation
α
= 1 , full compensation
α ≠ {
0 ,1 } , fractional compensation
Conventional & Fractional PC • Conventional PC schemes: – Attempt to maintain a constant SINR at the receiver – UE increases increases the Tx power to fully fully compensate compensate for increases in the path loss
• Fractional PC schemes: – Allow the received SINR to decrease as the path loss increases. – UE Tx power increases increases at a reduced rate as the path loss increases. Increases Increases in path loss are only partially compensated. compensated. [+]:: Improve air interface efficiency & increase average cell throughputs by reducing Inter-cell interference – [+] • 3GPP specifies fractional power power control for the PUSCH with the option to disable it & revert to conventional based on
UL SINR
Conventional Power Control: =1 If Path Loss increases by 10 dB the UE Tx power increases by 10 dB
UE Tx Power
UL SINR
UE Tx Power
Fractional Power Control: ! { 0 ,1}
If Path Loss increases by 10 dB the UE Tx power increases by < 10 dB
MCS dependent component PPUSCH(i) = min {PCMAX,10 log10 ( M PUSCH(i)) + PO_PUSCH( j ) + ( j ) ⋅ PL + ∆TF (i) + f (i)} [dBm] MPR∗ K s
∆ TF (i ) = 10 log10 ( 2
0
− 1)
for
K S
= 1 .25
Otherwise
deltaTfEnabled Enabled TB size (MCS) impact to UE PUSCH power calculation LNCEL; Yes/No; -
MPR = TBS/NRE with NRE : number of RE, TBS = Transport Block Size
• • • • •
TF = Transport Format Ks - Enabling/disabling Enabling/disabling of the transport transport format dependent dependent offset on on a per UE basis If this parameter is enabled, PUSCH power calculation in UE uplink power control equation takes the Transport Block size in account during the power calculation Could be seen as dynamic offset of the TX power: when the BTS changes the MCS for the UE then the UE indirectly may adapt the power Increase the power power if the Transport Format (MCS, TBS size, Number of Resource Blocks) it is so selected to increase the number of bits per Resource Element
UL PU PUSCH SCH Powe Powerr Contr Control ol - Par Parame ameter ter PPUSCH (i ) = min{ PCMAX ,10 log( M PUSCH (i )) + Po _ PUSCH Category
Parameter P0 PUSCH
Huawei CellUlpcComm.P0 NominalPUSCH ' CellUlpcComm.Pa LoCoe(( " )i* CellUlpc#edic.#el ta/cEnaled ()i* ()i* - Cloe Cloe Loop Loop Cell+l2oSwitc!.Ul PUSCH Power Switc! Pc+l2oSwitc! Control 3nnerLoopPuc!S witc!
Value -80 dB dBm
& )0.8* 0 )o((* on
+
⋅ PL + ∆ TF (i ) +
Nokia Value Ericssons [LNCEL] -80 dB dBm [EUtranCell"##] p0NomPuc! p$eroNominalPuc! [LNCEL] % )alp!a ,* [EUtranCell"##] alp!a ulpc+lp!a [LNCEL] 0 delta(Enaled [LNCEL] 6 actUlpc/et!od )Puc!CLPucc [LNCEL] !CL* ulpcLowle4Sc! -,06 dBm [LNCEL] -78 dBm ulpcUple4Sc! ,8 [LNCEL] ,0 ulpcLow5ualSc! [LNCEL] ulpcUp5ualSc!
f (i )}
Value Z TE Value -80 -80 dBm dBm [Pow [Power erCo Con ntrol trolUL UL]] -%& p0NominalPUSCH dBm 8 )0.8* [PowerControlUL] & )0.8* alp!a [PowerControlUL] 1 0
[PowerControlUL] witc!"orCLPCo(PUS CH
,
UL PU PUSC SCH H Mess Messge ge 3 Po Powe werr Co Cont ntro roll - Pa Para rame mete terr
When LTE LTE PUSCH carry Message 3, transmit transmit power of Ue’s PUSCH is calculated as follow: PPUSCH (i ) = min{PCMAX ,10 log( M PUSCH (i )) + PO_pre
Category Parameter Huawei PUSCH /26 preamlem preamlem26 26 [CellUlpcComm] [CellUlpcComm] Power Control #eltaPreamle/26
Value 9 ): dB*
Nokia [LNCEL] deltaPre/26
+ ∆ PREAMBLE _ Msg 3 +
Value , )9 dB*
PL + ∆ TF (i ) + f (i )}
Ericssons
Value
ZT E [PowerControlUL] deltaPreamle/26
Value 0
UL-PC: PUCCH UL-PC:
UL-PC: PUCCH PPUCCH (i ) = min{ PMAX , P0_PUCCH ( j ) + PL + h(nCQI , n HARQ ) + ∆ F_PUCCH ( F ) + g (i)} [dBm] PPUCCH: PUCCH Power in subframe i
p0NomPucch
Pmax: max. allowed power
Nominal Power for UE PUCCH Tx Power Calculation LNCEL; -126..-96; 1; -100 dB
P0_PUCCH(j) = P0_NOMINAL_PUCCH(j) + P0_UE_PUCCH(j) P0_NOMINAL_PUCCH : cell specific (SysInfo) P0_UE_PUCCH : UE specific (RRC) PL: pathloss pathloss [dB] = referenceSignalPower referenceSignalPower – higher layer filtered RSRP H(nCQI, nHARQ ) • PUCCH format 1, 1a, 1b: h(n) = 0
* For PUCCH higher degree of orthogonality could be assumed due to the usage of the orthogonal codes so alpha=1 (full compensation)
• PUCCH format 2, 2a, 2b and : h(n) = 0 if n CQI < 4 h(n) = 10log10 (nCQI /4) otherwise (here: normal CP, for extented CP also nHARQ to be considered, n:number of information bits)
∆F_PUCCH
(F) : dFListPUCCH
(see next slide)
g(i): TPC (closed loop adjustment)
Compensation Factor for different PUCCH formats For example if format 1a (1ACK) is having offset 0 then format 1b
delta de ltaFL FLis istP tPUC UCCH CH Pa Para rame meter ters s Name
Object
Abbreviation
Range
Description
Default
DeltaF PUCCH List
LNCEL
dFListPucch
n/ a
dFListPucch: SEQUENCE (see values below)
n/a
DeltaF PUCCH Format 1
LNCEL
dFpucchF1
-2, 0, 2 dB
Used to define the PUCCH form at 1
0 dB
DeltaF PUCCH Format 1b
LNCEL
dFpucchF1b
1, 3, 5 dB
Used to define the PUCCH form at 1b
1 dB
DeltaF PUCCH Format 2
LNCE
dFpucchF2
-2, 0, 1, 2 dB
Used to define the PUCCH form at 2
0 dB
DeltaF PUCCH Format 2a
LNCE
dFpucchF2a
-2, 0, 2 dB
Used to define the PUCCH form at 2a
0 dB
DeltaF PUCCH Format 2b
LNCEL
dFpucchF2b
-2, 0, 2 dB
Used to define the PUCCH form at 2b
0 dB
UL PU PUCCH CCH Powe Powerr Contr Control ol - Par Parame ameter ter PPUCCH (i) = min{PCMAX , P0 _ PUCCH + PL+ h nCQI, n HARQ Category
PUCCH Power Control
Parameter
Huawei
Value
Nokia
Value
+ ∆F _ PUCCH (F ) + g(i)} Ericssons
P0 nomin nominal al PUCCH PUCCH [CellU [CellUlpc lpcCom Comm] m] -,0& dBm [LNCEL] p0NomPucc! -,00 dBm [EUtranCell"##] P0NominalPUCCH p$eroNominalPucc! Cloe Cloe Loo Loop p Swit Switc! c! [Cel [CellP lPc+ c+l2 l2o] o] 0 Pucc!CloeLoopPc
[LNCEL] ulpcLowle4Cc! -,06 dBm 3nnerLoopPucc!Switc! [LNCEL] ulpcUple4Cc! -78 dBm [LNCEL] ulpcLow5ualCc! , [LNCEL] ulpcUp5ualCc! : Period o( Power control PUCCH uter Loop Power Control
[CellPc+l2o] Pucc!PcPeriod [Cell+l2oSwitc!] UlPc+l2oS UlPc+l2oSwitc witc! !uterLoopPucc!Switc!
Value -7; dBm
Z TE [PowerControlUL] poNominalPUCCH
[PowerControlUL] delta"Pucc!"ormat, [PowerControlUL] delta"Pucc!"ormat, [PowerControlUL] delta"Pucc!"ormat9 [PowerControlUL] delta"Pucc!"ormat9a [PowerControlUL] delta"Pucc!"ormat9 [PowerControlUL] witc!"orCLPCo(PUCCH
,0 )900 m* , )on*
N?+
N?+
N?+
Value -,0& dBm
9 )9 dB* , )6 dB* 9 ), dB* 9 )9 dB* 9 )9 dB*
,
UL-PC: Control Control Scheme Scheme UL-PC:
UL-PC: Control Scheme Open loop: level based Interference: considered by P0 values not need for explicit signaling RRC-BCCH : RRC-BCCH: P0_NOMINAL_PUSCH, P 0_NOMINAL_PUCCH, ALPHA, ALPHA, deltaFListPUCCH, deltaPreambleMsg3
PDCCH:: DELTA_PUSCH, DELTA_PUCCH PDCCH MPUSCH taken from scheduling grant
Data
RRC-DCCH : P0_UE_PUSCH , P 0_UE_PUCCH, RRC-DCCH: DELTA_TF_ENABLED, ACCUMULATION_ENABLED, P_SRS_OFFSET, filterCoefficient
UE: PL
UL-PC: Closed Loop UL-PC:
UL-PC ULPC:: Clo Closed sed loo loop p - PUS PUSCH CH (exa (exampl mple) e) ulpcEnable enable UL closed loop PC LNCEL; true, false; false
Closed loop adjustments: f(i) = f(i-1) +
δPUSCH
(i - KPUSCH)
i.e. recursive determination
or
ulpcAccuEnable
f(i) = δPUSCH (i - KPUSCH) i.e. absolute setting where δPUSCH is the signaled TPC in subframe i-K PUSCH
PUSCH/PUCCH TPC commands accumulation enabled Vendor Specific
For FDD: KPUSCH = 4 whether the recursive or absolute method is used P (closed loop)
parameter Accumulation-enabled
UL-P UL -PC: C: Clo Close sed d Loop Loop - Pr Proc oces ess s SIB/RRC parameters: P0_NOMINAL_PUSCH, P0_UE_PUSCH, P0_NOMINAL_PUCCH, P0_UE_PUCCH, ALPHA, deltaFLi stPUCCH, DELTA_TF_ENABLED, ACCUMULATION_ENABLED, deltaPreambleMsg3, P_SRS_OFFSET, filterCoefficient
Per UE measurements of • receive power of wanted signal • interferen ce and noise
Calculation of average receive level per TTI. Calculation of SINR (two methods for I+N values) Transformation from Watt into dBm/dB domain.
Transformation into TF independent format
ENABLE_CLPC ENABLE_CLPC_PUSCH, ENABLE_CLPC_SRS; ENABLE_CLPC_PUCCH
time scale: TTI
SINR_MAX, SINR_MIN, RSSI_MAX, RSSI_MIN
Clipping using adjustable parameters
WF_PUSCH_UE, WF_PUSCH_CELL, WF_SRS_UE, WF_SRS_CELL, WF_PUCCH_UE, WF_PUCCH_CELL
Weighting
TAVG_PUSCH_SRS_CONT, TAVG_PUSCH_SRS_DISCONT, TAVG_PUCCH_CONT, TAVG_PUCCH_DISCONT
Long term filtering/averaging of level and SINR using adjustable filter coefficients
Periodic reading of averaged level and averaged SINR value (time constant adjustable) Comparison with twodimensiona l decision matrix. Calculation of DELTA_ PUSCH and DELTA_ PUCCH values for the UE Commanding DELTA_PUSCH
DELTA_TF_ENABLED, deltaFListPUCCH
ulpcPuschEn Including or excluding of RSSI and SINR measurements from PUSCH in the Closed Loop PC component LNCEL; true; true
ulpcPucchEn Including or excluding of RSSI and SINR measurements from PUCCH in the Closed Loop PC component LNCEL; true; true
FILTER_OUTPUT_PERIOD
time scale: filter output period (adjustable by O&M)
UP_LEV_PUSCH_SRS, LOW_LEV_PUSCH_SRS,, LOW_LEV_UP_QUAL_PUSCH_SRS, LOW_QUAL_PUSCH_SRS, UP_LEV_PUCCHPUCCH, UP_QUAL_PUCCH, LOW_QUAL_PUCCH, minCumDeltaPUSCH, maxCumDeltaPUSCH, minCumDeltaPUCCH, maxCumDeltaPUCCH
UL-P UL -PC: C: Clo Close sed d Loop Loop - Pr Proc oces ess s Measurements and Averaging Averaged* Averag ed* received level per TTI per UE:
Averaged* Av eraged* received SINR per TTI per UE:
• RSSIPUSCH/UE
Relevant for PUSCH and PUCCH: (I+N)UE and (I+N)cell
• RSSIPUCCH/UE
and and for for SRS: SRS: (I+N (I+N))cell
• RSSISRS/UE
(I+N)cell : all potential PRBs
relevant: PRBs allocated to the particular UE
(I+N)UE : allocated PRBs to the particular UE • SINRPUSCH/UE
* linear, but converted to dBm, dB for further deployment
• SINRPUSCH/cell • SINRPUCCH/UE • SINRPUCCH/cell • SINRSRS/cell
Transformation in independent format Normalization applies to:
UE and/or TF specific offsets get subtracted:
• PUSCH
• ∆TF
• PUCCH
• ∆PF_PUCCH
• SRS
• h(n) • PO_UE_PUSCH
UL-P UL -PC: C: Clo Close sed d Loop Loop - Pr Proc oces ess s Clipping Averaged Averag ed received level per TTI per UE:
Averaged Av eraged received SINR per TTI per UE:
RSSI*** := min(max(RSSImin,RSSI***)RSSImax)
SINR*** := min(max(SINRmin,SINR***)SINRmax)
*** PUSCH/UE,
PUCCH/UE,
*** PUSCH/UE, PUSCH/cell, PUCCH/UE, PUCCH/cell, SRS/cell
SRS/UE
Weighting of MCS independent measurements PUSCH PUSCH and SRS - composite composite SINR SINR and RSSI RSSI : C _ SINR PUSCH / SRS
=
SINR PUSCH / UE ⋅ WF _ PUSCH _ UE + SINR PUSCH / cell ⋅ WF _ PUSCH _ CELL WF _ PUSCH _ UE + WF _ PUSCH _ CELL
C _ RSSI PUSCH / SRS
=
+
SINR SRS / cell ⋅ WF _ SRS _ CELL
+ WF _ SRS _ CELL
RSSI PUSCH / UE ⋅ WF _ PUSCH _ UE + RSSI SRS / UE ⋅ WF _ SRS _ UE WF _ PUSCH _ UE + WF _ SRS _ UE
PUCCH PUCC H - composit composite e SINR and and RSSI RSSI : C _ SINR
PUCCH
=
SINR
PUCCH / UE
⋅ WF
C _ RSSI PUCCH = RSSI PUCCH / UE
_ PUCCH _ UE
+
SINR
WF _ PUCCH _ UE
+
WF _ PUCCH _ CELL
PUCCH / cell
⋅ WF
_ PUCCH _ CELL
Weighting factors WF_*** : range [1, 100]
UL-P UL -PC: C: Clo Close sed d Loop Loop - Pr Proc oces ess s Filtering RSSIPUSCH/SRS,filtered
SINRPUSCH/SRS,filtered
RSSIPUCCH,filtered
SINRPUCCH,filtered
Decision matrix for the
Decision matrix for the
PUSCH/SRS component
PUCCH component of
of the CLPC algorithm
the CLPC algorithm
ulpcReadPeriod
DELTA_PUSCH
DELTA_PUCCH
value
value
Low pass filter first order (exponential moving average) :
y ( n)
=
c ⋅ y ( n − 1) + (1 − c ) ⋅ x ( n)
x: input (composite RSSI, SINR)
c: filter coefficient
y: output (filtered RSSI, SINR)
c = exp(-T/T avg ) i.e. impact = (1/e) at t = -T -T avg
n: step, max frequency = 1/TTI
Example: T = 1ms, T avg = 25 ms
c = 0.96
Time interval for sending averaged RSSI and SINR values to the decision decis ion matrix to determine power corrections in Closed Loop uplink power control. LNCEL; 10…2000ms; 10ms; 50 ms
filterCoeff Filter coefficient for RSRP measurements used to calculate pathloss. Value fc0 corresponds to k = 0, fc1 corresponds to k = 1, and so on. LNCEL; fc0 (0), fc1 (1), fc2 (2), fc3 (3), fc4 (4), fc5 (5), fc6 (6), fc7 (7), fc8 (8), fc9 (9), fc11 (10), fc13 (11), fc15 f c15 (12), fc17 (13), fc19 (14); fc4(4)
UL-P PC: C: Parameters Parameter arameterss UL-PC:
UL-P UL -PC: C: Clo Close sed d Loop Loop - Pr Proc oces ess s ulpcUpqualSch
Decision matrix
1dB
High Thresh. For SINR for PUSCH LNCEL; -47...80dB; 1dB ; 11dB
SINR + 1 dB or
ulpcUpqualCch
- 1 dB
- 1 dB
+ 3 dB
High Thresh. For SINR for PUCCH LNCEL; -47...80dB; 1dB ; 4dB
1
2
3
UP_QUAL_**
+ 1 dB or
0 dB
-1 dB
+ 3 dB
4
LOW_QUAL_**
5
6
1dB
ulpcLowqualSch Low Thresh. For SINR for PUSCH LNCEL; -47...80dB; 1dB ; 8dB
+ 1 dB or
+ 1 dB or
+ 1 dB or
+ 3 dB
+ 3 dB
+ 3 dB
7
ulpcLowqualCch Low Thresh. For SINR for PUCCH LNCEL; -47...80dB; 1dB ; 1dB
LOW_LEV_**
ulpcLowlevCch Low Thresh. For RSSI for f or PUCCH LNCEL; -127...0dBm;1dBm ;-103dBm ;-103dBm
ulpcLowlevSch
8
UP_LEV_**
Decision whether to +1dB or +3dB 9
RSSI
ulpcUplevCch High Thresh. For RSSI for f or PUCCH LNCEL; -127...0dBm;1dBm ;-98dBm ;-98dBm
ulpcUplevSch
PRACH Power Control
LTE Uplink Power Control for PRACH
• The purpose of power control for the PRACH is to t o ensure the random access success rate while minimizing transmit power • The PRACH power is calculated using the following formula:
PPRACH
=
min{PCMAX , Po _ pre
CLTE ategoryPRACH Parampower eter P@+CH Power Control
+
PL + ∆ preamble
+
( N pre
− 1) ⋅ ∆ step }
awei Valwith ue Nokia Vformula a lue isHucalculated following :
P0pre
[@+CHC(2] Pream3nit@c4ar2etPwr
% )-,0; dBm*
[LNCEL] ulpc3niPrePwr
tep
[@+CHC(2] Pwr@ampin2Step
, )9 )9dB*
[LNCEL] prac!Pwr@amp
Ericssons
,9 )-78 dBm* [EUtranCel [EUtranCell"##] l"##] preamle3nitial@ecei4edar2etPower , )9 dB*
Value
Z TE
-,,0 -,,0 dBm dBm [Pra [Prac! c!"# "##] #] preamle3ni@ecei4edPower [Prac!"##] power@ampin2Step
Value ,0 )-,00 dBm* , )9 dB*
Noia !L !L--PC -PC
Nokia DL-PC RL20: (static) cell power reduction
dlCellPwrRed Reduction of DL Tx power; deducted from max. antenna TX power. LNCEL; 0..10; 0.1; 0 dB
• based on single parameter CELL_PWR_RED = 0.0, 0.1 … 10.0 dB • cell size adjustment and coverage control • flat Power Spectral Density (PSD)
pMax Maximum output power LNCEL; 37.0 (0), 39.0 (1), 40.0 (2), 41.8 (3), 43.0 (4), 44.8 (5), 46.0 (6), 47.8 (7);(7); 37.0 dBm = 5 W 39.0 dBm = 8 W 40.0 dBm = 10 W 41.8 dBm = 15 W 43.0 dBm = 20 W 44.8 dBm = 30 W 46.0 dBm = 40 W 47.8 dBm = 60 W
• semi-static MIMO_COMP (if enabled)
RL30: optional power boost: PCFICH, PHICH, DL RS
PSD
PSD
PSD = (Max_TX_P (Max_TX_Pwr wr – CELL_PW CELL_PWR_ R_RED RED)) – 10*log10( 12*# 12*# PRBs) PRBs)
Allocated ocated DL PRB PRBs
Frequency
PSD PSD = (Max_TX (Max_TX_Pw _Pwrr – CELL_PW CELL_PWR_R R_RED ED)) – 10*log10( 12*# PRBs) PRBs)
PDCCH
Time
Nokia DL-PC: Power Reduction Cell Power Reduction PSD = (pMax (pMax - CEL CELL_PW L_PWR_R R_RED) ED) - 10*log1 10*log10( 0( # PRBs_D PRBs_DL L *12) *12) - MIM MIMO_C O_COMP OMP [dBm] [dBm]
PSD: Power Spectral Density, which specifies the constant absolute Power per 15kHz Resource Element (RE) • pMax: maximum eNodeB transmit power per Antenna in [dBm] • CELL_PWR_RED:
O&M parameter
• # PRBs_DL: maximum Number of downlink PRBs in given LTE Carrier Bandwidth • MIMO_COMP: Compensation Factor • MIMO_COMP MIMO_COMP = 0 dB for SISO/SIMO • MIMO_COMP MIMO_COMP = 0...12 dB for MIMO Diversity and for MIMO Spatial Multiplexing - PSD given per per antenna (RF amplifier output) output) - PRBs not not scheduled scheduled are blanked blanked
dlpcMimoComp Determines the power compensation factor for antennaspecific maximum power in case of a downlink transmission using at least two TX antennas LNCEL; 0..10; 0.01; 0 dB
Applied to UE / cell specific channels and signals: • PSD_CELL_CTRL for BCCH i.e. PBCH+PDSCH, PCFICH and PCH P CH • PSD_CELL_RS for reference signals (RS) / pilots
dlCellPwrRed
• PSD_CELL_SYNC for synchronization synchronization channel
Reduction of DL Tx power; deducted from max. antenna TX power. LNCEL; 0..10; 0.1; 0 dB
• PSD_UE_PDSCH for UE specific part of PDSCH • PSD_UE_CTRL for PDCCH and PHICH
Nokia DL-PC: DL power boosting for control channels • Power offsets to the PCFICH, PHICH, DL RS. • Introduced with RL30 (LTE430). • Better detection of PCFICH indicating the number of OFDM symbols for the PDCCH. P DCCH. • Better channel estimation in case of RS boosting may improve HO performance. performance. • Higher reliability of ACK/NACK transmission via PHICH. PCFICH OFDM symbols
The eNB ensures that total Tx power is not exceed, i.e. the sum power for any OFDM symbol must not n ot exceed the commited maximum power, otherwise all the configured boosts (PHICH) may not be applied. Subcarrier power boosting is only allowed if the excess power is withdrawn from the remaining subcarriers. Coverage in LTE is very often limited by UL, and in such cases it does not make much sense to improve the coverage in DL. UL coverage should be checked before applying DL control channels power boost. RS
Nokia DL-PC: DL power boosting for control channels PCFICH power boosting PCFICH provides information about the number of OFDM symbols for the PDCCH. The eNB supports dedicated power control settings for the PCFICH in order to ensure that especially cell edge UEs can properly receive the PCFICH. A relative offset between the flat PSD (Power Spectral Density) on PDSCH and PCFICH can be configured by O&M on cell level.
PHICH power boosting
dlPcfichBoost Downlink PCFICH transmission power boost LNCEL; 0..6; 0.1; 0 dB
dlPhichBoost
The PHICH provides ACK/NACK information for the uplink upli nk transmission. Downlink PHICH transmission power boost The eNB supports dedicated power control settings for the PHICH in order to ensure LNCEL; 0..6; 0.1; 0 dB that the UE can properly receive the PHICH. PHICH power boost may not be (fully) applied if PDCCH PSD goes too low in the first OFDM symbol. In that case, the eNB rises the t he PHICH Power Boost not applied warning. A maximum relative offset between the flat PSD on PDSCH and PHICH can be configured by O&M on cell level.
Downlink reference signal boosting dlRsBoost The downlink reference symbols are used by the UE for Downlink RS transmission power channel estimation and cell measurements (Level, Quality) for f or mobility. boost The eNB supports relative RS / PDSCH power control settings. LNCEL; 0dB (0), 1.77dB (1), 3dB A relative offset between the PDSCH and RS (2), 4.77dB (3), 6dB (4); 0 dB can be configured by O&M on cell level. le vel. The eNB ensures that total Tx power is not exceed. The sum power for any OFDM symbol must not exceed the commited maximum power, otherwise all the configured boosts
H"awei !L !L--PC -PC
Downlink Power Control Strategy Fixed Power Assignment. Applicable for :
Category
–CRS (Cell Reference Signal) –Synchronization Synchronization Signal –PBCH (Physical Broadcast Channel) –PCFICH (Physical Control Format Indicator Channel) –PHICH (Physical Hybrid-ARQ Indicator Channel) –PDCCH that carry common control information (SIB, RACH response, Paging) –PSDCH (Physical Downlink Shared Channel) The configured power must meet the requirement for downlink coverage coverage of the cell.
Parameter
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Parameter Cell+l2oSwitc!.#lPc+l2oS Cell+l2oSwitc!.#lPc+l2oSwitc! witc! Pdcc!PcSwitc!
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Huawei Value Nokia Value P#SCHC(2. ,8.9 dBm N?+. C@S power @e(erenceSi2nalPwr (or 90 watt calculated (rom :60 )90 watt* [LNCEL] p/aA ,000 )0 dB* [LNCEL] dl@Boot
CellC!PwrC(2. Sc!Pwr CellC!PwrC(2. Pc!Pwr CellC!PwrC(2. Pc(ic!Pwr Cell+l2oSwitc!. #lPc+l2oSwitc! P!ic!3nnerLoopPcS witc! (( Cell#lpcP!ic!. Pwr((et CellC!PwrC(2. @a@pPwr CellC!PwrC(2. Pc!Pwr CellC!PwrC(2. #c!Pwr P#SCHC(2.P Cell#lpcPdc!Pa.Pa Pc(( Cell+l2oSwitc!.
Ericssons N?+. C@S power calculated (rom [SectorE5uipment"unction] con(i2uredutputPower [EUtranCell"##] crain
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Value ,9 dBm
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!L-PC: PC on P!CCH !L-PC:
Main target of DL-PC-CCH • DL Power Control for PDCCH is an additional mechanism interacting with DL AMC for PDCCH in order to make the signaling as robust as possible • DL-PC-CCH aims at 1% target BLER but cannot modify AGG assignments • Main actions performed by DL-PC-CCH – Power reduction on CCEs with assigned AGG level higher than required (or equal) – Power boosting on CCEs with assigned AGG level lower than required – Equal power relocation among all scheduled CCEs • Macro cell case #1 • Uniform UE distribution
enableLowAgg
4-CCE 8-CCE
Very good CCEs (CQI highly above 1% BLER target) Bad CCEs (AGG level too high to meet 1% BLER target) available , relocate equally among all CCEs If still some power available,
2-CCE
1-CCE
Enable lower aggregation selection for PDCCH LA . LNCEL; True/False; False
Principles of DL-PC-AMC • PDCCH Power Control can be enabled/disabled by O&M switch Amplifier cannot be exceeded (pMax ; O&M) • Maximum transmit power of the Power Amplifier • Reduction and boosting range is strictly defined and is always considered as the limit for power level modification • DL-PC-CCH operates together with DL-AMC-CCH on TTI basis • DCI messages with more than one CCE (AGG-…>1) have a flat PSD, transmitted with w ith the same power thus all CCEs belonging to one scheduled UE are transmitted Short Name
Description
Range/ Step
Default Value
Parameter Scope
true, false
true
Cell
Changing parameter requires object locking. Operator configurable.
Remark
enablePcPdcch
Enabling/disabling PC for PDCCH. In case the parameter is disabled, a flat downlink PSD is used.
pdcchPcBoost
Maximum power boost per CCE.
0...10 dB, step 0.1 dB
4 dB
BTS
Not modifiable. Vendor configurable.
pdcchPcRed
Maximum power reduction per CCE.
0...10 dB, step 0.1 dB
6 dB
BTS
Not modifiable. Vendor configurable.
pdcchPcReloc
Maximum limit on the equal power relocation per CCE.
0...10 dB, step 0.1 dB
3 dB
BTS
Not modifiable. Vendor configurable.
General algorithm Output from DL AMC for PDCCH • Required AGG levels per UE per DCI format • Assigned AGG levels per UE per DCI format f ormat • PDCCH CQI per UE • Calculated TOTAL_NUM_CCEs (all available CCEs; PHICH&PCFICH considered) Build the Power Basket (“free unused” power on PDCCH)
Power Relocation If the Power Basket is still not empty, relocate the excess power equally among all scheduled UEs. • power levels to be applied for all scheduled UEs
Count unused power from unscheduled CCEs Power Reduction Decrease the power for all UEs with assigned AGG level equal to the required AGG level to meet the 1% BLER target and count the amount to the Power Basket Power Boosting Increase the power for all UEs with the assigned AGG level lower than the required AGG level to meet the 1% BLER target. Modify the Power Basket according to the amount of power used for boosting.
…to DL-PHY
#race$"l Cell Sh"tdown
Graceful Cell Shutdown Reduced Service Impact • Stepwise downlink power reduction in order to enforce active and idle mode mobility to other cells layers
• Operator configurable settings
enableGrflShdn The parameter enables the feature 'Graceful Cell Shutdown'. LNBTS; Disabled (0), Enabled (1); Enabled (1)
DL power
time handover or cell reselection
Graceful Cell Shutdown • The eNode B reduces stepwise the DL power to a minimum power level
• The number of steps and the shutdown time is operator configurable
• The broadcasted power for the reference symbols is not changed, i.e. UE assumes that the eNode B power is unchanged
• A wait timer of 10 seconds is applied after the last power down step before the administrative state is set to locked and the operational state is set to disabled. shutdownStepAmount
shutdownWindow
Number of Steps for Graceful Cell Shutdown LNBTS; 1...16;1; 6
Time Interval for Stepwise Output Power Reduction for Graceful Cell Shutdown LNBTS; 6...180;6; 60
PM Counter & dependencies • No new PM counters are added as the graceful shutdown behavior can be covered with the existing PM counters
• No dependencies on other entities
Questions 1. What is the purpose of the ulpcAlpha parameter. 2. Assuming that the RSSI signal increased above the level set by ulpcUplevSch AND the received quality was between ulpcLowqualSch and ulpcUpqualSch - what would would be the the closed closed loop loop power power control control decision decision value? 3. What is the purpose of PDCCH CCE Power Boosting?
%HAN 'OU
