LTE Parameter - Admission Control

(1)

Power Control & Power Setting

(2)

Overview

(3)

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

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)

dlCellPwrRed

Reduction of DL Tx power; deducted from max. antenna TX power.

(4)

UL

(5)

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

Interference (I)

- main cause: inter-cell

Signal strength S:

Depends on PL, indoor loss etc.,

i.e. location

Low

High

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.

(6)

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)

1) Initial TX power level 2) SINR measurment

3) Setting new power offset 4) TX power level

adjustment with the new offset

(7)

UL

(8)

UL-PC: PUSCH Equation

*PH = Power Headroom

[

dBm

]

i

f

i

PL

j

P

i

M

P

i

P

_PUSCH

(

)

=

min

{

_CMAX

,

10 log

₁₀

(

_PUSCH

(

))

+

_{O_PUSCH}

(

)

+

α

(

)

⋅

+

∆

_TF

(

)

+

(

)}

Open Loop (OL)

Closed Loop (CL)

(9)

UL-PC: PUSCH

[

dBm

]

i

f

i

PL

j

P

i

M

P

i

P

_PUSCH

(

)

=

min

{

_CMAX

,

10 log

₁₀

(

_PUSCH

(

))

+

_{O_PUSCH}

(

)

+

α

(

)

⋅

+

∆

_TF

(

)

+

(

)}

P

_PUSCH

(i) :PUSCH Power in subframe i

P

_CMAX

: max. allowed UE power

(23 dBm for class 3)

M

_PUSCH

: number of scheduled RBs

(The UE Tx. Power increases proportionally to # of PRBs)

P

_{O_PUSCH}

(j) = P

_{O_NOMINAL_PUSCH}

(j) +

_{PO_UE_PUSCH}

(j)

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

∆

_TF

(i) = 10 log 10 (

2MPR Ks

_{– 1) for K}

s

= 1.25 else 0, MPR = TBS/N

RE

, N

RE

: number of RE

Ks defined by deltaMCS-Enabled, UE specific

f(i): TPC (Closed Loop adjustment)

{

M

i

P

j

PL

i

f

i

}

[ ]

dB

P

i

PH

(

)

=

_CMAX

−

10 log

₁₀

(

_PUSCH

(

))

+

_{O_PUSCH}

(

)

+

α

⋅

+

∆

_TF

(

)

+

(

)

_{PH = Power Headroom}

j : This can be 0 or 1, j = 0, 1 come from higher layer

Semi-persistant: j=0 / dynamic scheduling: j=1

P

_{O_NOMINAL_PUSCH}

(0,1): cell specific (SysInfo)

P

_{O_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

P

_{O_NOMINAL_PUSCH}

(2): P

_{O_PRE}

+ ∆

_{Preamble_Msg3}

P

_{O_UE_PUSCH}

(2) = 0

α

(2) = 1.0 (i.e. full PL compensation)

(10)

Open Loop PC vs. Closed Loop PC

PL

j

P

Po

Operating

Basic

_

int

=

_{O_PUSCH}

(

)

+

α

(

)

⋅

Open Loop Power Control

Target: provide a basic operating point for a suitable PSD for an

average

MCS (average SINR):

• 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

(11)

Open Loop PC

P

_{O_PUSCH}

(j) = P

_{O_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

P

_{O_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)

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

[

dBm

]

i

f

i

PL

j

P

i

M

P

i

P

_PUSCH

(

)

=

min

{

_CMAX

,

10 log

₁₀

(

_PUSCH

(

))

+

_{O_PUSCH}

(

)

+

α

(

)

⋅

+

∆

_TF

(

)

+

(

)}

p0NomPusch

Nominal Power for UE PUSCH Tx Power Calculation

(12)

PUSCH Formula

Alpha

This path loss compensation factor a is adjustable by

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}

α ≠

_{{ 0 ,1 } , fractional compensation}

PL: pathloss [dB] = referenceSignalPower –

higher layer filtered RSRP

ulpcAlpha

LNCEL; 0, 0.4..1.0; 0.1;1.0

[

dBm

]

i

f

i

PL

j

P

i

M

P

i

(13)

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

Conventional Power

Control: α=1

If Path Loss

increases by 10 dB

the UE Tx power

increases by 10 dB

Fractional

Power Control:

α

≠ { 0 ,1}

If Path Loss

increases by 10

dB the UE Tx

power increases

by < 10 dB

UE Tx Power UE Tx Power UL SINR UL SINR

(14)

MCS dependent component

[

dBm

]

i

f

i

PL

j

P

i

M

P

i

P

_PUSCH

(

)

=

min

{

_CMAX

,

10 log

₁₀

(

_PUSCH

(

))

+

_{O_PUSCH}

(

)

+

α

(

)

⋅

+

∆

_TF

(

)

+

(

)}

25 .

1 =

S

K

for

)

1

2 (

log

10 )

(

=

₁₀

−

∆

MPR

∗

K

s

TF

i

• 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

MPR = TBS/N

_RE

with N

_RE

: number of RE, TBS = Transport Block Size

0 Otherwise

deltaTfEnabled

Enabled TB size (MCS) impact to UE PUSCH power calculation LNCEL; Yes/No;

(15)

-UL PUSCH Power Control - Parameter

Category

Parameter

Huawei

Value

Nokia

Value

Ericssons

Value

ZTE

Value

PUSCH Power

Control

P0 PUSCH

CellUlpcComm.P0

NominalPUSCH

-80 dBm

[LNCEL]

p0NomPusch

-80 dBm

[EUtranCellFDD]

pZeroNominalPusch

-80 dBm [PowerControlUL]

p0NominalPUSCH

-75

dBm

α

CellUlpcComm.Pa

ssLossCoeff

5 (0.8)

[LNCEL]

ulpcAlpha

7 (alpha 1) [EUtranCellFDD] alpha

8 (0.8)

[PowerControlUL]

alpha

5 (0.8)

ΔTF (i)

CellUlpcDedic.Del

taMcsEnabled

0 (off)

[LNCEL]

deltaTfEnabled

0 [PowerControlUL] ks

0 f(i) - Close Loop

Switch

CellAlgoSwitch.Ul

PcAlgoSwitch

-InnerLoopPuschS

witch

on

[LNCEL]

actUlpcMethod

[LNCEL]

ulpcLowlevSch

[LNCEL]

ulpcUplevSch

[LNCEL]

ulpcLowqualSch

[LNCEL]

ulpcUpqualSch

3 (PuschCLPucc

hCL)

-103 dBm

-98 dBm

18

10 [PowerControlUL]

switchForCLPCofPUS

CH

1 )}

(

)

(

))

(

log(

10 ,

min{

)

(

i

P

M

i

P

_{_}

PL

i

f

i

(16)

UL PUSCH Messge 3 Power Control - Parameter

)}

(

)

(

))

(

log(

10 ,

min{

)

(

i

P

M

i

P

_{O_pre} _{_} ₃

PL

i

f

i

P

_PUSCH

=

_CMAX _PUSCH

+

∆

_PREAMBLE _Msg

+

∆

_TF

+

Category

Parameter

Huawei

Value

Nokia

Value

Ericssons

Value

ZTE

Value

PUSCH Msg3

Power Control

Δ preamble_msg3 [CellUlpcComm]

DeltaPreambleMsg3

2 (4 dB)

[LNCEL]

deltaPreMsg3

1 (2 dB)

[PowerControlUL]

deltaPreambleMsg3

0 When LTE PUSCH carry Message 3, transmit power of Ue’s PUSCH is calculated as follow:

(17)

UL

(18)

UL-PC: PUCCH

[

dBm

]

i

g

F

n

h

PL

j

P

i

P

_PUCCH

(

)

=

min{

_MAX

,

_{0_PUCCH}

(

)

+

(

_CQI

,

_HARQ

)

+

∆

_{F_PUCCH}

(

)

+

(

)}

P

_PUCCH

: PUCCH Power in subframe i

P

_max

: max. allowed power

P

_{0_PUCCH}

(j) = P

_{0_NOMINAL_PUCCH}

(j) + P

_{0_UE_PUCCH}

(j)

P

_{0_NOMINAL_PUCCH}

: cell specific (SysInfo)

P

_{0_UE_PUCCH}

: UE specific (RRC)

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

H(n

_CQI,

n

_HARQ

)

• PUCCH format 1, 1a, 1b: h(n) = 0

• PUCCH format 2, 2a, 2b and :

h(n) = 0 if n

_CQI

< 4

h(n) = 10log

₁₀

(n

_CQI

/4) otherwise

(here: normal CP, for extented CP also n

_HARQ

to be considered, n:number of information bits

)

∆

_{F_PUCCH}

(F) : dFListPUCCH

(see next slide)

g(i): TPC (closed loop adjustment)

* For PUCCH higher degree of orthogonality could be assumed due to the usage of the orthogonal codes so alpha=1 (full

compensation)

Compensation Factor for different PUCCH formats

For example if format 1a (1ACK) is having offset 0 then format 1b (2ACK) could have offset 3dB

p0NomPucch

Nominal Power for UE

PUCCH Tx Power Calculation LNCEL; -126..-96; 1;-100 dB

(19)

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

(20)

UL PUCCH Power Control - Parameter

(

n

,

)

(

)

(

)}

h

,

min{

)

(

i

P

₀_{_}

PL

_CQI

n

_{_}

F

g

i

P

_PUCCH

=

_CMAX _PUCCH

+

_HARQ

+

∆

_F _PUCCH

+

Category

Parameter

Huawei

Value

Nokia

Value

Ericssons

Value

ZTE

Value

PUCCH Power Control

P0 nominal PUCCH [CellUlpcComm] P0NominalPUCCH

-105 dBm [LNCEL] p0NomPucch -100 dBm [EUtranCellFDD] pZeroNominalPucch

-96 dBm [PowerControlUL] poNominalPUCCH

-105 dBm

Close Loop Switch [CellPcAlgo]

PucchCloseLoopPcType 0 (NOT_USE_P0N OMINALPUCCH) ΔF_PUCCH [CellUlpcComm] DeltaFPUCCHFormat1 [CellUlpcComm] DeltaFPUCCHFormat1b [CellUlpcComm] DeltaFPUCCHFormat2 [CellUlpcComm] DeltaFPUCCHFormat2a [CellUlpcComm] DeltaFPUCCHFormat2b 1 (0 dB) 1 (3 dB) 2 (1 dB) 2 (2 dB) 2 (2 dB) [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) [PowerControlUL] deltaFPucchFormat1 [PowerControlUL] deltaFPucchFormat1b [PowerControlUL] deltaFPucchFormat2 [PowerControlUL] deltaFPucchFormat2a [PowerControlUL] deltaFPucchFormat2b 2 (2 dB) 1 (3 dB) 2 (1 dB) 2 (2 dB) 2 (2 dB)

g(i) - Close Loop Switch [CellAlgoSwitch] UlPcAlgoSwitch – InnerLoopPucchSwitch On [LNCEL] actUlpcMethod [LNCEL] ulpcLowlevCch [LNCEL] ulpcUplevCch [LNCEL] ulpcLowqualCch [LNCEL] ulpcUpqualCch 3 (PuschCLPucchCL) -103 dBm -98 dBm 1 4 [PowerControlUL] switchForCLPCofPUCCH 1 Period of Power control [CellPcAlgo] PucchPcPeriod 10 (200 ms)

PUCCH Outer Loop Power Control

[CellAlgoSwitch] UlPcAlgoSwitch -OuterLoopPucchSwitch

(21)

UL

(22)

UL-PC: Control Scheme

Open loop: level based

Interference: considered by P

₀

values

not need for explicit signaling

RRC-BCCH

:

P

_{0_NOMINAL_PUSCH}

, P

_{0_NOMINAL_PUCCH}

, ALPHA, deltaFListPUCCH, deltaPreambleMsg3

Data

UE: PL

SIB1, UE class: P

_CMAX

PDCCH

: DELTA_PUSCH, DELTA_PUCCH

M

_PUSCH

taken from scheduling grant

RRC-DCCH

: P

_{0_UE_PUSCH}

, P

_{0_UE_PUCCH}

,

DELTA_TF_ENABLED,

ACCUMULATION_ENABLED,

P_SRS_OFFSET, filterCoefficient

(23)

UL

(24)

UL-PC: Closed loop - PUSCH (example)

Closed loop adjustments:

f(i) = f(i-1) + δ

δ

_PUSCH

(i - K

_PUSCH

)

i.e. recursive determination

or

f(i) = δ

δ

_PUSCH

(i - K

_PUSCH

)

i.e. absolute setting

where

δ

_PUSCH

is the signaled TPC in subframe i-K

_PUSCH

For FDD: K

_PUSCH

= 4

whether the recursive or absolute method is used

parameter Accumulation-enabled

P (closed loop)

t

ulpcAccuEnable

PUSCH/PUCCH TPC commands accumulation enabled Vendor Specific

ulpcEnable

enable UL closed loop PC LNCEL; true, false;false

(25)

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

Periodic reading of averaged level and averaged SINR value (time constant adjustable)

Weighting

Comparison with two-dimensional 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

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.

Clipping using adjustable parameters

Transformation into TF independent format

Long term filtering/averaging of level and SINR using adjustable filter coefficients

time scale: TTI

time scale: filter output period (adjustable by O&M) DELTA_TF_ENABLED, deltaFListPUCCH ENABLE_CLPC ENABLE_CLPC_PUSCH, ENABLE_CLPC_SRS; ENABLE_CLPC_PUCCH

SINR_MAX, SINR_MIN, RSSI_MAX, RSSI_MIN

WF_PUSCH_UE, WF_PUSCH_CELL,

WF_SRS_UE, WF_SRS_CELL, WF_PUCCH_UE, WF_PUCCH_CELL 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 TAVG_PUSCH_SRS_CONT, TAVG_PUSCH_SRS_DISCONT, TAVG_PUCCH_CONT, TAVG_PUCCH_DISCONT FILTER_OUTPUT_PERIOD DELTA_PUSCH, DELTA_PUCCH

ulpcPucchEn

Including or excluding of RSSI and SINR measurements from PUCCH in the Closed Loop PC component

LNCEL; true;true

ulpcPuschEn

Including or excluding of RSSI and SINR measurements from PUSCH in the Closed Loop PC component

(26)

UL-PC: Closed Loop - Process

**Averaged* received level per TTI per UE:**

• RSSI

_PUSCH/UE

• RSSI

_PUCCH/UE

• RSSI

_SRS/UE

relevant: PRBs allocated to the particular UE

**Averaged* received SINR per TTI per UE:**

Relevant for PUSCH and PUCCH: (I+N)

_UE

and (I+N)

_cell

and for SRS: (I+N)

_cell

(I+N)

_cell

: all potential PRBs

(I+N)

_UE

: allocated PRBs to the particular UE

• SINR

_PUSCH/UE

• SINR

_PUSCH/cell

• SINR

_PUCCH/UE

• SINR

_PUCCH/cell

• SINR

_SRS/cell

Measurements and Averaging

* linear, but converted to dBm, dB for further deployment

Transformation in independent format

• ∆

_TF

• ∆

_{PF_PUCCH}

• h(n)

• P

_{O_UE_PUSCH}

• P

_{O_UE_PUCCH}

Normalization applies to:

UE and/or TF specific offsets get subtracted:

• PUSCH

• PUCCH

(27)

UL-PC: Closed Loop - Process

Averaged received SINR per TTI per UE:

SINR

_***

:= min(max(SINR

_min

,SINR

_***

)SINR

_max

)

*** PUSCH/UE, PUSCH/cell, PUCCH/UE, PUCCH/cell, SRS/cell

Clipping

Weighting of MCS independent measurements

Averaged received level per TTI per UE:

RSSI

_***

:= min(max(RSSI

_min

,RSSI

_***

)RSSI

_max

)

*** PUSCH/UE, PUCCH/UE, SRS/UE

CELL SRS WF CELL PUSCH WF UE PUSCH WF CELL SRS WF SINR CELL PUSCH WF SINR UE PUSCH WF SINR SINR

C _PUSCH _SRS PUSCH UE PUSCH cell SRS cell

_ _ _ _ _ _ _ _ _ _ _ _ _ _/ / / / + + ⋅ + ⋅ + ⋅ =

UE

SRS

WF

UE

PUSCH

WF

UE

SRS

WF

RSSI

UE

PUSCH

WF

RSSI

C

_PUSCH _SRS PUSCH UE SRS UE

_

_/ / /

+

⋅

+

⋅

=

PUSCH and SRS - composite SINR and RSSI

:

PUCCH - composite SINR and RSSI

:

CELL

PUCCH

WF

UE

PUCCH

WF

CELL

PUCCH

WF

SINR

UE

PUCCH

WF

SINR

C

PUCCH UE PUCCH cell PUCCH

_

/ /

+

⋅

+

⋅

=

UE PUCCH PUCCH

RSSI

(28)

UL-PC: Closed Loop - Process

Decision matrix for the PUSCH/SRS component of the CLPC algorithm RSSI_{PUSCH/SRS,filtered} DELTA_PUSCH value SINR_{PUSCH/SRS,filtered}

Decision matrix for the PUCCH component of the CLPC algorithm RSSI_{PUCCH,filtered} DELTA_PUCCH value SINR_{PUCCH,filtered}

Filtering

x: input (composite RSSI, SINR) y: output (filtered RSSI, SINR) n: step, max frequency = 1/TTI

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

Low pass filter first order (exponential moving average)

:

)

(

)

1 (

)

1 (

)

(

n

c

y

n

c

x

n

y

=

⋅

−

+

−

⋅

c: filter coefficient

c = exp(-T/T_avg) i.e. impact = (1/e) at t = -T_avg Example: T = 1ms, T_avg= 25 ms c = 0.96

ulpcReadPeriod

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)

(29)

UL

(30)

UL-PC: Closed Loop - Process

LOW_QUAL_** UP_QUAL_** LOW_LEV_** 2 3 5 6 4 7 + 1 dB or + 3 dB SINR RSSI -1 dB - 1 dB - 1 dB + 1 dB or + 3 dB + 1 dB or + 3 dB + 1 dB or + 3 dB + 1 dB or + 3 dB 0 dB 8 9 UP_LEV_** 1

Decision matrix

ulpcUpqualSch

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

ulpcUpqualCch

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

ulpcLowqualSch

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

ulpcLowqualCch

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

ulpcLowlevCch

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

ulpcLowlevSch

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

ulpcUplevCch

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

ulpcUplevSch

High Thresh. For RSSI for PUSCH LNCEL; -127...0dBm;1dBm ;-98dBm 1dB 1dB Decision whether to +1dB or +3dB

(31)

PRACH Power Control

(32)

LTE Uplink Power Control for PRACH

LTE PRACH power is calculated with following formula :

}

)

1 (

,

min{

_CMAX

_o

_{_}

_pre

_preamble

_pre

_step

PRACH

P

PL

N

P

=

+

∆

+

−

⋅

∆

Category

Parameter

Huawei

Value

Nokia

Value

Ericssons

Value

ZTE

Value

PRACH Power Control P0_pre [RACHCfg] PreambInitRcvTargetPwr 7 (-106 dBm) [LNCEL] ulpcIniPrePwr 12 (-98 dBm) [EUtranCellFDD] preambleInitialReceivedTargetPower -110 dBm [PrachFDD] preambleIniReceivedPower 10 (-100 dBm) Δ step [RACHCfg] PwrRampingStep 1 (2dB) [LNCEL] prachPwrRamp 1 (2 dB) [PrachFDD] powerRampingStep 1 (2 dB)

• 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

(33)

Nokia DL

(34)

Nokia DL-PC

RL20: (static) cell power reduction

• 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)

• semi-static MIMO_COMP (if enabled)

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

PSD

Frequency

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

Allocated DL PRBs

DL Pilots

PSD

Time

PDCCH

BCH, SCH

PDSCH, PCH

PSD

Frequency

Allocated DL PRBs

DL Pilots

PSD

Time

PDCCH

BCH, SCH

PDSCH, PCH

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); -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

dlCellPwrRed

(35)

Nokia DL-PC: Power Reduction

Cell Power Reduction

PSD = (pMax - CELL_PWR_RED) - 10log10( # 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

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

• PSD_CELL_SYNC for synchronization channel

• PSD_UE_PDSCH for UE specific part of PDSCH

• PSD_UE_CTRL for PDCCH and PHICH

dlCellPwrRed

LNCEL; 0..10; 0.1;0 dB

dlpcMimoComp

Determines the power

compensation factor for antenna-specific maximum power in case of a downlink transmission using at least two TX antennas

(36)

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.

RS

OFDM

symbols

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.

(37)

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

The PHICH provides ACK/NACK information for the uplink transmission.

The eNB supports dedicated power control settings for the PHICH in order to ensure 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

The downlink reference symbols are used by the UE for

channel estimation and cell measurements (Level, Quality) for mobility. The eNB supports relative RS / PDSCH power control settings.

A relative offset between the PDSCH and RS 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.

dlRsBoost

Downlink RS transmission power boost

LNCEL; 0dB (0), 1.77dB (1), 3dB (2), 4.77dB (3), 6dB (4);0 dB

dlPcfichBoost

Downlink PCFICH transmission power boost

LNCEL; 0..6; 0.1; 0 dB

dlPhichBoost

Downlink PHICH transmission power boost

(38)

Huawei DL

(39)

Downlink Power Control Strategy

Fixed Power Assignment. Applicable for :

–

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.

Category Parameter Huawei Value

Fix DL Power Allocation

CRS PDSCHCfg.ReferenceSignalPwr 18.2 dBm for 20 watt RRU Syncronization Signal CellChPwrCfg.SchPwr -6 dB

PBCH CellChPwrCfg.PbchPwr -6 dB PCFICH CellChPwrCfg.PcfichPwr -6 dB PHICH CellAlgoSwitch.DlPcAlgoSwitch -PhichInnerLoopPcSwitch Off CellDlpcPhich.PwrOffset Off 0 dB PDSCH (SIB, RACH response, Paging) CellChPwrCfg.RaRspPwr, CellChPwrCfg.PchPwr, CellChPwrCfg.DbchPwr 0 dB -6 dB -6 dB

PDSCH Other than SIB, RACH response & Paging

PDSCHCfg.Pb

CellDlpcPdschPa.PaPcOff

1 dB -3 dB

• Dynamic Power Control. Applicable for

–PDCCH (Physical Downlink Control Channel) that carry Dedicated Control Information.

Category Parameter Huawei Nokia Ericssons ZTE

Dynamic Power Control PDCCH

CellAlgoSwitch.DlPcAlgoSwitch -PdcchPcSwitch

(40)

Downlink Power Control Parameter

Category Parameter Huawei Value Nokia Value Ericssons Value ZTE Value

Fix DL Power Allocation CRS PDSCHCfg. ReferenceSignalPwr 18.2 dBm for 20 watt N/A. CRS power calculated from [LNCEL] pMax [LNCEL] dlRsBoost -430 (20 watt) 1000 (0 dB)

N/A. CRS power calculated from [SectorEquipmentFunction] configuredOutputPower [EUtranCellFDD] crsGain -40000 300 (3 dB) [EUtranCellFDD] cellReferenceSignalPower 12 dBm Syncronization Signal CellChPwrCfg. SchPwr -6 dB PBCH CellChPwrCfg. PbchPwr -6 dB [PowerControlDL] paForBCCH 4 (0 dB) PCFICH CellChPwrCfg. PcfichPwr -6 dB dlPcfichBoost 0 [PowerControlDL] pcfichPwrOfst PHICH CellAlgoSwitch. DlPcAlgoSwitch -PhichInnerLoopPcS witch Off CellDlpcPhich. PwrOffset Off 0 dB dlPhichBoost 0 [PowerControlDL] phichPwrOfst PDSCH (SIB, RACH response, Paging) CellChPwrCfg. RaRspPwr, CellChPwrCfg. PchPwr, CellChPwrCfg. DbchPwr 0 dB -6 dB -6 dB PDSCH Other than SIB, RACH

response & Paging

PDSCHCfg.Pb CellDlpcPdschPa.Pa PcOff 1 dB -3 dB [EUtranCellFDD] pdschTypeBgain 1 [EUtranCellFDD] Pb 1 Dynamic Power Control PDCCH Switch CellAlgoSwitch. DlPcAlgoSwitch -PdcchPcSwitch On enablePcPdcch 1 (true)

(41)

Cell specific Reference Signal (CRS) Power Setting

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

(42)

Cell specific Reference Signal (CRS) Power Setting

RS Power ＝

＝

＝ Total power per channel(dBm) – 10lg(total subcarrier)+10lg(P

B

+ 1)

Bandwidth

P

_B

P

_RS

( dBm)

10M

1

18.2 15M

1

16.4 20M

1

15.2

3/4 1 1 3/4 1 1 X 1 1 X 3/4 1 1 3/4 1 1 R 1 1 R 3/4 1 1 3/4 1 1 X 1 1 X 3/4 1 1 3/4 1 1 R 1 1 R

P

_B

=

2 , 2 Antennas

compensate

P

_B

Power of type B symbol / Power of type A

Symbol

1 ANT port

2 or 4 ANT ports

0

1 5/4

1 4/5

1

2 3/5

3/4

3 2/5

1/2

(43)

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

(44)

Pa-Pb Power Distribution for 20W, 10 MHz

Power utilization rate PA

-6 -4.77 -3 -1.77 0 1 2 3 PB 0 _67% _75% _86% _92% _100% _97% _94% _92% 1 75% 86% 100% 92% 83% 80% 77% 75% 2 86% 100% 83% 75% 67% 63% 61% 58% 3 100% 83% 67% 58% 50% 47% 44% 42% Max RS power(dBm) PA -6 -4.77 -3 -1.77 0 1 2 3 PB 0 19.4 18.8 17.5 16.7 15.2 14.2 13.2 12.2 1 20.0 19.3 18.2 17.0 15.2 14.2 13.2 12.2 2 20.5 20.0 18.2 17.0 15.2 14.2 13.2 12.2 3 21.2 20.0 18.2 17.0 15.2 14.2 13.2 12.2

Total Power of symbol with RS(W) PA

-6 -4.77 -3 -1.77 0 1 2 3 PB 0 20.0 20.0 20.0 20.0 20.0 19.3 18.8 18.3 1 20.0 20.0 20.0 18.3 16.7 16.0 15.4 15.0 2 20.0 20.0 16.7 15.0 13.3 12.6 12.1 11.7 3 20.0 16.7 13.3 11.7 10.0 9.3 8.8 8.3

Total Power of symbol without RS(W) PA

-6 -4.77 -3 -1.77 0 1 2 3 PB 0 13.4 15.0 17.2 18.5 20.0 20.0 20.0 20.0 1 15.0 17.1 20.0 20.0 20.0 20.0 20.0 20.0 2 17.2 20.0 20.0 20.0 20.0 20.0 20.0 20.0 3 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0

(45)

DL

(46)

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

1-CCE

8-CCE 2-CCE

4-CCE

•Macro cell case #1

•Uniform UE distribution

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

enableLowAgg

Enable lower aggregation selection for PDCCH LA .

(47)

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

Remark

enablePcPdcch Enabling/disabling PC for PDCCH. In case the parameter is disabled, a flat downlink PSD is used.

true, false true Cell Changing parameter requires object locking.

Operator configurable.

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

Vendor configurable.

pdcchPcReloc Maximum limit on the equal power relocation per CCE.

0...10 dB, step 0.1 dB

(48)

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)

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

…to DL-PHY

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.

Build the Power Basket

(“free unused” power on PDCCH)

(49)

Graceful Cell Shutdown

(50)

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

DL power

time

handover or

cell reselection

enableGrflShdn

The parameter enables the feature 'Graceful Cell Shutdown'. LNBTS; Disabled (0), Enabled (1);Enabled (1)

(51)

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

Number of Steps for Graceful Cell Shutdown

LNBTS; 1...16;1;6

shutdownWindow

Time Interval for Stepwise Output Power Reduction for Graceful Cell Shutdown LNBTS; 6...180;6;60