LTE Parameter - Admission Control

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 • eNodeB gives fixed power density per PRB scheduled for transport. – Total Tx power is max. when all PRBs are 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) – Calculated at the UE based on pathloss measurements • 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

ULUL-PC: Overview

UL-PC: Overview LTE: orthogonal UL Tx, i.e. near-far-problem much less severe than WCDMA • UL: dynamic, slow PC – Open Loop (OL) & Closed Loop (CL) • 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 cause: inter-cell Noise (N) = kB T ∆f + NFeNB

Power control does not control the absolute UE Tx power but the Power Spectral Density (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 controls the Tx power to keep the transmitted power spectral density (PSD) constant independent of the allocated transmit bandwidth (#PRBs)

• If no feedback from eNodeB ( in the PDCCH UL PC command) the UE performs open loop PC based on path loss measurements

• If feedback from eNodeB the UE corrects the PSD when receiving PC commands from eNodeB ( in the PDCCH UL PC 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

ULUL-PC: PUSCH

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) + α ( 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) + α ( 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 class 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: pathloss [dB] = referenceSignalPower – higher layer filtered RSRP ∆TF (i) = 10 log 10 (2MPR Ks – 1) for Ks = 1.25 else 0, MPR = TBS/NRE, 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 from higher layer Semi-persistant: j=0 / dynamic 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 PO_NOMINAL_PUSCH(2): PO_PRE + ∆Preamble_Msg3 α (2) = 1.0 (i.e. full PL compensation)

PO_UE_PUSCH(2) = 0

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 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 to the channel conditions (take into account e.g. fast fading) • Correct the estimations of power from the open loop PC ulpcEnable enable UL closed loop PC LNCEL; true, false; false

Open Loop PC PPUSCH(i) = min {PCMAX,10 log10 (M PUSCH(i)) + PO_PUSCH( j ) + α ( j) ⋅ PL + ∆TF (i) + f (i)} [dBm]

PO_PUSCH(j) = PO_NOMINAL_PUSCH(j) + PO_UE_PUSCH(j) j=0 -> PUSCH transmission with semi-persistent 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 level for all mobiles in 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 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) + α ( j ) ⋅ PL + ∆TF (i) + f (i)} [dBm]

PL: pathloss [dB] = referenceSignalPower – higher layer filtered RSRP

This path loss compensation factor a is adjustable by

Alpha

O&M. α is a cell - specific parameter (broadcasted on BCH).

α ∈ [0.0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0] α = 0 , no compensation α = 1 , full compensation ulpcAlpha LNCEL; 0, 0.4..1.0; 0.1; 1.0

α ≠ { 0 ,1 } , fractional compensation

Conventional & Fractional PC • Conventional PC schemes: – Attempt to maintain a constant SINR at the receiver – UE increases the Tx power to fully 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 at a reduced rate as the path loss increases. Increases in path loss are only partially compensated. – [+]: Improve air interface efficiency & increase average cell throughputs by reducing Inter-cell interference • 3GPP specifies fractional power control for the PUSCH with the option to disable it & revert to conventional based on α

UL SINR

Conventional Power Control: α=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: α ≠ { 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 ) + α ( j ) ⋅ PL + ∆TF (i) + f (i)} [dBm]

∆ TF (i ) = 10 log10 (2 MPR∗K s − 1) 0

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 of the transport format dependent offset 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 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 PUSCH Power Control - Parameter PPUSCH (i ) = min{ PCMAX ,10 log( M PUSCH (i )) + Po _ PUSCH + α ⋅ PL + ∆ TF (i ) + f (i )} Category

Parameter P0 PUSCH

Huawei CellUlpcComm.P0 NominalPUSCH α CellUlpcComm.Pa ssLossCoeff ΔTF (i) CellUlpcDedic.Del taMcsEnabled f(i) - Close Loop CellAlgoSwitch.Ul PUSCH Power Switch PcAlgoSwitch Control InnerLoopPuschS witch

Value Nokia Value Ericssons -80 dBm [LNCEL] -80 dBm [EUtranCellFDD] p0NomPusch pZeroNominalPusch 5 (0.8) [LNCEL] 7 (alpha 1) [EUtranCellFDD] alpha ulpcAlpha 0 (off) [LNCEL] 0 deltaTfEnabled on [LNCEL] 3 actUlpcMethod (PuschCLPucc [LNCEL] hCL) ulpcLowlevSch -103 dBm [LNCEL] -98 dBm ulpcUplevSch 18 [LNCEL] 10 ulpcLowqualSch [LNCEL] ulpcUpqualSch

Value ZTE Value -80 dBm [PowerControlUL] -75 p0NominalPUSCH dBm 8 (0.8) [PowerControlUL] 5 (0.8) alpha [PowerControlUL] ks 0 [PowerControlUL] switchForCLPCofPUS CH

1

UL PUSCH Messge 3 Power Control - Parameter

When LTE PUSCH carry Message 3, transmit power of Ue’s PUSCH is calculated as follow: PPUSCH (i ) = min{PCMAX ,10 log( M PUSCH (i )) + PO_pre + ∆ PREAMBLE _ Msg 3 + PL + ∆ TF (i ) + f (i )}

Category Parameter Huawei PUSCH Msg3 Δ preamble_msg3 [CellUlpcComm] Power Control DeltaPreambleMsg3

Value Nokia 2 (4 dB) [LNCEL] deltaPreMsg3

Value 1 (2 dB)

Ericssons

Value

ZTE [PowerControlUL] deltaPreambleMsg3

Value 0

ULUL-PC: PUCCH

UL-PC: PUCCH PPUCCH (i ) = min{ PMAX , P0_PUCCH ( j ) + PL + h(nCQI , nHARQ ) + ∆ 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 [dB] = 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 nCQI < 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 (2ACK) could have offset 3dB

deltaFListPUCCH Parameters 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 format 1

0 dB

DeltaF PUCCH Format 1b

LNCEL

dFpucchF1b

1, 3, 5 dB

Used to define the PUCCH format 1b

1 dB

DeltaF PUCCH Format 2

LNCE

dFpucchF2

-2, 0, 1, 2 dB

Used to define the PUCCH format 2

0 dB

DeltaF PUCCH Format 2a

LNCE

dFpucchF2a

-2, 0, 2 dB

Used to define the PUCCH format 2a

0 dB

DeltaF PUCCH Format 2b

LNCEL

dFpucchF2b

-2, 0, 2 dB

Used to define the PUCCH format 2b

0 dB

UL PUCCH Power Control - Parameter PPUCCH(i) = min{PCMAX, P0 _ PUCCH + PL+ h(nCQI, nHARQ) + ∆F _ PUCCH(F) + g(i)} Category

PUCCH Power Control

Parameter

Huawei

Value

P0 nominal PUCCH [CellUlpcComm] -105 dBm P0NominalPUCCH Close Loop Switch [CellPcAlgo] 0 PucchCloseLoopPcType (NOT_USE_P0N OMINALPUCCH) 1 (0 dB) ΔF_PUCCH [CellUlpcComm] DeltaFPUCCHFormat1 1 (3 dB) [CellUlpcComm] DeltaFPUCCHFormat1b [CellUlpcComm] 2 (1 dB) DeltaFPUCCHFormat2 [CellUlpcComm] 2 (2 dB) DeltaFPUCCHFormat2a [CellUlpcComm] 2 (2 dB) DeltaFPUCCHFormat2b On g(i) - Close Loop [CellAlgoSwitch] Switch UlPcAlgoSwitch – InnerLoopPucchSwitch

Period of Power control PUCCH Outer Loop Power Control

[CellPcAlgo] PucchPcPeriod [CellAlgoSwitch] UlPcAlgoSwitch OuterLoopPucchSwitch

Value

Ericssons

Value

[LNCEL] p0NomPucch

Nokia

-100 dBm

[EUtranCellFDD] pZeroNominalPucch

-96 dBm

[LNCEL] dFpucchF1 [LNCEL] dFpucchF1b [LNCEL] dFpucchF2 [LNCEL] dFpucchF2a [LNCEL] dFpucchF2b

1 (0 dB) 0 (1 dB) 1 (0 dB) 1 (0 dB) 1 (0 dB)

ZTE [PowerControlUL] poNominalPUCCH

[PowerControlUL] deltaFPucchFormat1 [PowerControlUL] deltaFPucchFormat1b [PowerControlUL] deltaFPucchFormat2 [PowerControlUL] deltaFPucchFormat2a [PowerControlUL] deltaFPucchFormat2b [PowerControlUL] switchForCLPCofPUCCH

[LNCEL] actUlpcMethod 3 (PuschCLPucchCL) [LNCEL] ulpcLowlevCch -103 dBm -98 dBm [LNCEL] ulpcUplevCch [LNCEL] ulpcLowqualCch 1 4 [LNCEL] ulpcUpqualCch

10 (200 ms) 1 (on)

N/A

N/A

N/A

Value -105 dBm

2 (2 dB) 1 (3 dB) 2 (1 dB) 2 (2 dB) 2 (2 dB)

1

ULUL-PC: Control Scheme

UL-PC: Control Scheme Open loop: level based Interference: considered by P0 values

not need for explicit signaling

RRC-BCCH: P0_NOMINAL_PUSCH, P0_NOMINAL_PUCCH, ALPHA, deltaFListPUCCH, deltaPreambleMsg3

PDCCH: DELTA_PUSCH, DELTA_PUCCH MPUSCH taken from scheduling grant

Data

RRC-DCCH: P0_UE_PUSCH, P0_UE_PUCCH, DELTA_TF_ENABLED, ACCUMULATION_ENABLED, P_SRS_OFFSET, filterCoefficient

UE: PL SIB1, UE class: PCMAX

ULUL-PC: Closed Loop

UL-PC: Closed loop - PUSCH (example) 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-KPUSCH

PUSCH/PUCCH TPC commands accumulation enabled Vendor Specific

For FDD: KPUSCH = 4 whether the recursive or absolute method is used

parameter Accumulation-enabled

P (closed loop)

t

UL-PC: Closed Loop - Process SIB/RRC parameters: P0_NOMINAL_PUSCH, P0_UE_PUSCH, P0_NOMINAL_PUCCH, P0_UE_PUCCH, ALPHA, deltaFListPUCCH, DELTA_TF_ENABLED, ACCUMULATION_ENABLED, deltaPreambleMsg3, P_SRS_OFFSET, filterCoefficient

Per UE measurements of • receive power of wanted signal • interference 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 twodimensional decision matrix. Calculation of DELTA_ PUSCH and DELTA_ PUCCH values for the UE Commanding DELTA_PUSCH and DELTA_PUCCH values to the UE via PDCCH

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

DELTA_PUSCH, DELTA_PUCCH

UL-PC: Closed Loop - Process Measurements and Averaging Averaged* received level per TTI per UE:

Averaged* received SINR per TTI per UE:

• RSSIPUSCH/UE

Relevant for PUSCH and PUCCH: (I+N)UE and (I+N)cell

• RSSIPUCCH/UE

and for SRS: (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 • PO_UE_PUCCH

UL-PC: Closed Loop - Process Clipping Averaged received level per TTI per UE:

Averaged 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 and SRS - composite SINR and RSSI : C _ SINR PUSCH

/ SRS

=

SINR PUSCH

C _ RSSI PUSCH / SRS =

/ UE

⋅ WF _ PUSCH _ UE + SINR PUSCH / cell ⋅ WF _ PUSCH _ CELL + SINRSRS / cell ⋅ WF _ SRS _ CELL WF _ PUSCH _ UE + WF _ PUSCH _ CELL + WF _ SRS _ CELL

RSSI PUSCH / UE ⋅ WF _ PUSCH _ UE + RSSI SRS / UE ⋅ WF _ SRS _ UE WF _ PUSCH _ UE + WF _ SRS _ UE

PUCCH - composite SINR and RSSI : C _ SINR

PUCCH

=

SINR

PUCCH

/ UE

⋅ WF _ PUCCH _ UE + SINR PUCCH / cell ⋅ WF _ PUCCH WF _ PUCCH _ UE + WF _ PUCCH _ CELL

C _ RSSI PUCCH = RSSI PUCCH / UE

_ CELL

Weighting factors WF_*** : range [1, 100]

UL-PC: Closed Loop - Process Filtering RSSIPUSCH/SRS,filtered

SINRPUSCH/SRS,filtered

Decision matrix for the PUSCH/SRS component of the CLPC algorithm

RSSIPUCCH,filtered

SINRPUCCH,filtered

Decision matrix for the PUCCH component of the CLPC algorithm

ulpcReadPeriod

DELTA_PUSCH value

DELTA_PUCCH 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/Tavg) i.e. impact = (1/e) at t = -Tavg

n: step, max frequency = 1/TTI

Example: T = 1ms, Tavg = 25 ms

Initialization: y(0) := target RSSI/SINR

c = 0.96

Time interval for sending averaged RSSI and SINR values to the decision 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 (12), fc17 (13), fc19 (14); fc4(4)

ULUL-PC: Parameters

UL-PC: Closed Loop - Process ulpcUpqualSch

Decision matrix

1dB

High Thresh. For SINR for PUSCH LNCEL; -47...80dB; 1dB ; 11dB

SINR + 1 dB or + 3 dB

ulpcUpqualCch High Thresh. For SINR for PUCCH LNCEL; -47...80dB; 1dB ; 4dB

- 1 dB

- 1 dB

1

2

3

UP_QUAL_** + 1 dB or + 3 dB

0 dB

-1 dB

4

LOW_QUAL_**

5

6

1dB

ulpcLowqualSch + 1 dB or + 3 dB

Low Thresh. For SINR for PUSCH LNCEL; -47...80dB; 1dB ; 8dB

+ 1 dB or + 3 dB 7

ulpcLowqualCch Low Thresh. For SINR for PUCCH LNCEL; -47...80dB; 1dB ; 1dB

LOW_LEV_**

ulpcLowlevCch Low Thresh. For RSSI for PUCCH LNCEL; -127...0dBm;1dBm ;-103dBm

Decision whether to +1dB or +3dB

+ 1 dB or + 3 dB 8

UP_LEV_**

9

RSSI

ulpcUplevCch High Thresh. For RSSI for PUCCH LNCEL; -127...0dBm;1dBm ;-98dBm

ulpcLowlevSch

ulpcUplevSch

Low Thresh. For RSSI for PUSCH LNCEL; -127...0dBm;1dBm ;-103dBm

High Thresh. For RSSI for PUSCH LNCEL; -127...0dBm;1dBm ;-98dBm

PRACH Power Control

LTE Uplink Power Control for PRACH

• The purpose of power control for the PRACH is to ensure the random access success rate while minimizing transmit power • The PRACH power is calculated using the following formula:

PPRACH = min{PCMAX , Po _ pre + PL + ∆ preamble + ( N pre − 1) ⋅ ∆ step } Category Parameter LTE PRACH power PRACH Power Control

Value Nokia Value isHuawei calculated with following formula :

P0_pre

[RACHCfg] PreambInitRcvTargetPwr

7 (-106 dBm)

[LNCEL] ulpcIniPrePwr

Δ step

[RACHCfg] PwrRampingStep

1 (2dB)

[LNCEL] prachPwrRamp

Ericssons

12 (-98 dBm) [EUtranCellFDD] preambleInitialReceivedTargetPower 1 (2 dB)

Value

ZTE

-110 dBm [PrachFDD] preambleIniReceivedPower [PrachFDD] powerRampingStep

Value 10 (-100 dBm) 1 (2 dB)

Nokia DLDL-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

• semi-static MIMO_COMP (if enabled)

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);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

RL30: optional power boost: PCFICH, PHICH, DL RS

PSD

PSD

PSD = (Max_TX_Pwr – CELL_PWR_RED) – 10*log10( 12*# PRBs)

Allocated DL PRBs

Frequency

DL Pilots

PSD = (Max_TX_Pwr – CELL_PWR_RED) – 10*log10( 12*# PRBs)

PDCCH

Time

PDSCH, PCH BCH, SCH

Nokia DL-PC: Power Reduction Cell Power Reduction PSD = (pMax - CELL_PWR_RED) - 10*log10( # PRBs_DL *12) - MIMO_COMP [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 = 0 dB for SISO/SIMO • MIMO_COMP = 0...12 dB for MIMO Diversity and for MIMO Spatial Multiplexing - PSD given per antenna (RF amplifier output) - PRBs not scheduled are 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 • PSD_CELL_RS for reference signals (RS) / pilots

dlCellPwrRed

• PSD_CELL_SYNC for 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. • Better channel estimation in case of RS boosting may improve HO 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 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 OFDM

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 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 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 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. 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 (PHICH) may not be applied.

Huawei DLDL-PC

Downlink Power Control Strategy Fixed Power Assignment. Applicable for :

Category

–CRS (Cell Reference Signal) –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 of the cell.

Parameter CRS Syncronization Signal PBCH PCFICH PHICH

Fix DL Power Allocation

Huawei Value PDSCHCfg.ReferenceSignalPwr 18.2 dBm for 20 watt RRU CellChPwrCfg.SchPwr -6 dB CellChPwrCfg.PbchPwr -6 dB CellChPwrCfg.PcfichPwr -6 dB Off CellAlgoSwitch.DlPcAlgoSwitch PhichInnerLoopPcSwitch Off 0 dB CellDlpcPhich.PwrOffset CellChPwrCfg.RaRspPwr, CellChPwrCfg.PchPwr, CellChPwrCfg.DbchPwr

0 dB -6 dB -6 dB

PDSCH Other than SIB, PDSCHCfg.Pb RACH response & Paging CellDlpcPdschPa.PaPcOff

1 dB -3 dB

PDSCH (SIB, RACH response, Paging)

• Dynamic Power Control. Applicable for –PDCCH (Physical Downlink Control Channel) that carry Dedicated Control Information. Category Dynamic Power Control PDCCH

Parameter CellAlgoSwitch.DlPcAlgoSwitch PdcchPcSwitch

Huawei On

Nokia On

Ericssons N/A

ZTE N/A

Downlink Power Control Parameter Category

Parameter CRS

Syncronization Signal PBCH PCFICH PHICH Fix DL Power Allocation

PDSCH (SIB, RACH response, Paging)

PDSCH Other than SIB, RACH response & Paging Dynamic Power Switch Control PDCCH

Huawei Value Nokia Value Ericssons N/A. CRS power calculated PDSCHCfg. 18.2 dBm N/A. CRS power ReferenceSignalPwr for 20 watt calculated from 430 (20 watt) from [LNCEL] pMax 1000 (0 dB) [SectorEquipmentFunction] [LNCEL] dlRsBoost configuredOutputPower [EUtranCellFDD] crsGain CellChPwrCfg. -6 dB SchPwr CellChPwrCfg. -6 dB PbchPwr CellChPwrCfg. -6 dB dlPcfichBoost 0 PcfichPwr CellAlgoSwitch. Off dlPhichBoost 0 DlPcAlgoSwitch PhichInnerLoopPcS 0 dB witch Off CellDlpcPhich. PwrOffset 0 dB CellChPwrCfg. RaRspPwr, -6 dB CellChPwrCfg. PchPwr, CellChPwrCfg. -6 dB DbchPwr 1 dB [EUtranCellFDD] PDSCHCfg.Pb -3 dB pdschTypeBgain CellDlpcPdschPa.Pa PcOff On enablePcPdcch 1 (true) CellAlgoSwitch. DlPcAlgoSwitch PdcchPcSwitch

Value 40000

ZTE [EUtranCellFDD] cellReferenceSignalPower

Value 12 dBm

[PowerControlDL] paForBCCH [PowerControlDL] pcfichPwrOfst [PowerControlDL] phichPwrOfst

4 (0 dB)

[EUtranCellFDD] Pb

1

300 (3 dB)

1

Cell specific Reference Signal (CRS) Power Setting

Type A Symbol: without RS REs

Type B Symbol: RS REs

EPRE: Energy Per Resource Element The power setting is based on EPRE EA (EPRE Type A) = Energy Per RE that doesn’t have Rs Power in the symbol EB (EPRE Type B) = Energy Per RE that have Rs Power in the symbol ER = Energy per Reference Signal Power RE

Cell specific Reference Signal (CRS) Power Setting 3/4 1

1

3/4 1

1

X

compensate

1

1

3/4 1

1

3/4 1

1

R

X

1 ANT port

2 or 4 ANT ports

0

1

5/4

1

4/5

1

1

3/4 1

1

2

3/5

3/4

3/4 1

1

3

2/5

1/2

1

1

3/4 1

1

3/4 1

1

R

1

1

R

Power of type B symbol / Power of type A Symbol

1

X

compensate

PB

X

R

PB=2 , 2 Antennas

Bandwidth

PB

PRS ( dBm)

10M

1

18.2

15M

1

16.4

20M

1

15.2

2 antennas, 20w per antenna

RS Power ＝ Total power per channel(dBm) – 10lg(total subcarrier)+10lg(PB + 1)

RRU Power Case Example Optimal power setting need to utilize all the RRU power. Accumulative power of type A should be equal to accumulative power of type B configuration possibilities: Type A Symbol -> 12 EA Type B Symbol -> 8EB + 2ER So Pa, Pb settings have to follow -> 8EB+2Er=12 EA Pa,Pb (-3,1) -> Er=2Ea, Eb=Ea 8Eb+2Er=12Ea 8Ea+2(2Ea)=12Ea 12Ea=12Ea Pa,Pb) (0,0) -> Er= Ea, Eb=1.25Ea 8Eb+2Er=12Ea 10Ea+2(Ea)=12Ea 12Ea=12Ea

So, optimal power setting combination is Pa,Pb = -3, 1 and Pa, Pb = 0, 0 Other setting can’t utilize total power 100%. See next slide

Pa-Pb Power Distribution for 20W, 10 MHz Power utilization rate

PB

0 1 2 3 Max RS power(dBm)

PB

0 1 2 3

Total Power of symbol with RS(W)

PB

0 1 2 3

Total Power of symbol without RS(W)

PB

0 1 2 3

PA -6

-4.77

-3

-1.77

0

1

2

3

67% 75% 86% 100%

75% 86% 100% 83%

86% 100% 83% 67%

92% 92% 75% 58%

100% 83% 67% 50%

97% 80% 63% 47%

94% 77% 61% 44%

92% 75% 58% 42%

0 15.2 15.2 15.2 15.2

1 14.2 14.2 14.2 14.2

2 13.2 13.2 13.2 13.2

3 12.2 12.2 12.2 12.2

0 20.0 16.7 13.3 10.0

1 19.3 16.0 12.6 9.3

2 18.8 15.4 12.1 8.8

3 18.3 15.0 11.7 8.3

0 20.0 20.0 20.0 20.0

1 20.0 20.0 20.0 20.0

2 20.0 20.0 20.0 20.0

3 20.0 20.0 20.0 20.0

PA -6 19.4 20.0 20.5 21.2

-4.77 18.8 19.3 20.0 20.0

-3 17.5 18.2 18.2 18.2

-1.77 16.7 17.0 17.0 17.0 PA

-6 20.0 20.0 20.0 20.0

-4.77 20.0 20.0 20.0 16.7

-3 20.0 20.0 16.7 13.3

-1.77 20.0 18.3 15.0 11.7 PA

-6 13.4 15.0 17.2 20.0

-4.77 15.0 17.1 20.0 20.0

-3 17.2 20.0 20.0 20.0

-1.77 18.5 20.0 20.0 20.0

DLDL-PC: PC on PDCCH

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) If still some power available, relocate equally among all CCEs

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 • Maximum transmit power of the Power Amplifier cannot be exceeded (pMax; O&M) • 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, thus all CCEs belonging to one scheduled UE are transmitted with the same power 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 • 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

Graceful Cell Shutdown

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 be the closed loop power control decision value? 3. What is the purpose of PDCCH CCE Power Boosting?

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