RANPAR Combined LoadControl v1.2

8/12/2019 RANPAR Combined LoadControl v1.2

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2 Nokia Siemens Networks RN 3167-30A / AA / 04_2011

Load Control:

Module Objectives

At the end of the module you will be able to:

Describe the principles of Load Control and it's parameters in detail

Describe the relationships of Load Control with AC and PS

Identify the parameters influencing BTS load measurements


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Load Control

Load Control Functions

Radio Interface Load

Power based Radio Resource Management

Throughput based Radio Resource Management

Planning thresholds for cell loading

BTS Measurements and Reporting Common Measurements

Dedicated Measurements

Filtering of Measurements


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Load Control Functional Overview

LCis a cell based RRM Function, utilising cell specific:

thresholds set by RNP, load measurements,

AC, PS & LC algorithms.

LCperforms the function of load control

in association with AC & PS

LCupdates load status using resource measurements & estimations provided by AC & PS

Continuously feeds cell load information to the other RRM functions, e.g. PS & AC

LC

AC

PSRM

RNC


5/235 Nokia Siemens Networks RN 3167-30A / AA / 04_2011

Load Control Functional Overview

RRM in RNC

LC

AC

PS

Load changeestimations

Load changeestimations

Schedul ing

per iod

PRACH load

measurement

WBTS NB/RSNBAP-PRIVATE:

RRIndPeriod o r

3GPP NBAP :

COMMONMEASUREMENT

REPORT

Dedicatedmeasurement report ing

parameters

parameters

measurements

est imat ions

when

changed Load change info

Load status request

Load status

NRT load

measurements



Load Control



Power based Radio Resource Management


Planning thresholds for cell loading

BTS Measurements and Reporting Common Measurements





NSN RRM: Power & Throughput based

DLuses Power Measurementsand calculations for RRM decisions

ULuses Power & Throughputestimations and calculations for RRM decisions

=

=N

jjUL loadi

1

)1(hNRP

P

totalrx

noiserx

UL

111

_

_-=-=h

max,_

_

BTStx

totaltx

DLP

P=h

definingLoad

= 0% 100%

jjbj

j

NE

RWL

1

/

/1

1

0

=

definingLittle i

Slide 9/10


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Load Estimation Methods and other cell interference

Throughputbased

threshold

WidebandPowerbased

threshold

Own cell load factor(capacity)

i=0.5

i=0

i=1

2 Load estimation

methods:


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UL power based load measurement

PRx_Own

PRxTotal = PRx_Own + PRx_Other + PNoise

=PRx_NRT + PRx_RT + PRx_Other + PNoise

= PRx_NRT + PRx_NC

PRx_Other

iUL= PRx_Other/ PRx_Own


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DL power based load measurement

PTx_Own

PTxTotal = PTx_Own

=PTx_NRT + PTx_RT + PTx_Common

= PTx_NRT + PTx_NC

PTx_Common

PRx_Own_DL

PRx_Other_DL

iDL= PRx_Other_DL/ PRx_Own_DL


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The BTS measures the total received power (PrxTotal) and the total transmitted power

(PtxTotal) on cell basis

The BTS reports PrxTotal& PtxTotalof each cell to the RNC

LC updates

Cell load status for each cell based on RADIO RESOURCE INDICATION

Non-controllable UL (PrxNC) & DL (PtxNC) load in cell

Semi-controllable UL (Prx_SC) & DL (Ptx_SC) load in the cell (related to PS Streaming)

ACand PSalgorithms work on the current cell load status provided by LC

Denying call admission(AC) & throttling back NRT traffic(PS) are the overload actions

After scheduling PS provides LC with PrxNRT, PtxNRT & LNRTestimates

After admitting RT RAB, AC provides LC with NC load increase estimate


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System Noise & PrxNoise Autotuning Algorithm

System noise PrxNoiseis the sum of all stationary noises: thermal noise

interference caused by spurious emissions of other systems, noise caused by additional equipment such as repeaters

PrxNoisecan vary place to place & even time to time

PrxNoisesetting affects the capacity of cell: PrxNoisetoo low: overestimationof cell load and can lead to unnecessary call blocking

PrxNoisetoo high: underestimationof cell load and can lead to overload situation

RNC providesAutotuning-Toolto measure unloaded system noise:

PrxUnloaded; it adjusts PrxNoise parameter based on these measurements

PrxTotal = PrxUnloadedwhen own cell considered unloaded/ very low load;

LRTUnloadedRT& LNRTUnloadedNRT& no EDCH users in the cell

UnloadedRT& UnloadedNRTare RNC parameters (values for NRT: 1 %, RT: 2 %)

LRT &LNRT: UL load factor for own cell RT (AC estimates) & PS users (PS estimates)

PrxNoise updated by the autotuning algorithm based on PrxUnloaded

PrxNoise autotuning step size limited by PrxNoiseMaxTuneAbsolute

PrxNoiseWCEL: -130..-50; 0.1; -105 dBm

PrxNoiseAutotuningWCEL: 0 (Off) / 1 (On)

PrxNoiseMaxTuneAbsoluteWCEL: 0..60; 0.5; 255 dB

255 dB: Autotuning is not limited


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UL Preventive & Overload Thresholds

Prx Target [dB]

PrxTarget [dB] + PrxOffset [dB]

load factor

Range [0..1]

NoiseRise[dB]

Overloaded Area

Marginal Load Area

Feasible Load Area

PrxTarget: WCEL; 0 .. 30; 0.1;4dB

PrxOffset: WCEL; 0 .. 6; 0.1;1dB

dBLog h-- 110 10PrxTarget =


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DL Preventive & Overload Thresholds

Ptx Target [dBm]

Ptx Target [dBm] + PtxOffset [dB]

load factor

totaltransmitted

po

wer

PtxTotal[dBm]

Overloaded Area

Marginal Load Area

Feasible Load Area

Cell Maximum

PtxTarget: WCEL; -10 .. 50; 0.1;40 dBm

PtxOffset: WCEL; 0 .. 6; 0.1;1dB

PtxCellMax WCEL: 050; 0.1; 43dBm


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Load Control


Radio Interface Load Power based Radio Resource Management


BTS Measurements and Reporting

Common Measurements




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Common measurements taken & reported by WBTS

PtxTotalTransmitted Carrier Power

Nokia Private NBAP PtxNonHSPATransmitted Code Power of all codes not used for HSDPA

Nokia Private NBAP

PrxTotalReceived Total Wideband Power

Nokia Private NBAP

REPSReceived E-DCH Power Share

Nokia Private NBAP

Acknowledged PRACH preambles

Nokia Private NBAP

Provided HSDPA Bitrate

Provided HSUPA Bitrate

Required Power

RRM in RNC needs this information for Streaming mapped on HSPA

(NSTNon Scheduled Transmission)

Nokia Private part is protocol extension specified in 3GPP


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WBTS Common Measurements sent to CRNC

WBTS sends measurements periodically according setting of RRM parameter:

(Nokia Private part)

RADIO RESOURCE MEASUREMENT REPORT

RRIndPeriodRadio Resource Indication Period

WBTS; 200 .. 2000; 100; 400 ms

RACHloadIndicationPeriod

WBTS; 0 (Off); 1 .. 20; 1; 1 RRI report


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Measurement filtering & reporting criteria in BTS

BTS measurements are averaged/filtered in BTS before reporting

L1 filtering L3 filtering

Higher Layer filtering

BTS reports measurements to RNC when needed

Reporting criteria

Step 1:

L1 Filtering:

1 Frame = 10 ms

Step 2

L1 measurement period

(= L1 Filtering)

= 100 ms = 10 frames

(Slide 30)Step 3:

L3 Filtering:

RRI period = 400 ms(Slide 27)


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L1 Filtering: Prx and Ptx Total Measurements

Frame average measurements

Frame Prx and Ptx Totalmeasurements

=14

0

//15

1TotalPTotalP txrxtxrx

0 141 2 ...


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L3 filtering: Higher layer filtering

The Measurement Filter Coefficient (k) IE indicates how filtering of the measurementvalues shall be performed before measurement event evaluation and reporting.

The averaging shall be performed according to the following formula.

L1 measurement period is 100 ms(20 ms for Acknowledged PRACH preambles)

Filter response

32

33

34

35

36

37

38

39

40

41

42

t 1 3 5 7 911

13

15

17

19

21

23

25

27

29

31

33

Measurements

Value,

dB Measured

Filtered, k = 3

Filtered, k = 7

Filter response

-105.5

-105

-104.5

-104

-103.5

-103

-102.5

-102

-101.5

t 1 3 5 7 911

13

15

17

19

21

23

25

27

29

31

33

Measurements

Value,

dB Measured

Filtered, k = 3

Filtered, k = 7

The higher the coefficient value, the more

emphasis on old filtered measurements

Examples:

k=2, a=0,5both an old filtered measurement and

a new measurement have the weight of 50%

K = 0a = 1no L3 filtering

MeasFiltCoeffMeasurement filter

coefficient kWCEL; 0 (Off); 1 ..

14; 1; 5


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Measurement filtering

The RNC can order BTSs to report cell-based & connection-based measurements only if internal

thresholds are exceeded.

However, a report is sent at least once per 10 reporting periods(RNP parameters).

The filtering functionality decreases the amount of measurement messages between the BTS and the

RNC and thus decreases the load of RNC computer units.

Internally RNC repeats the cell based measurements every WBTS: RRIndPeriodto provide RRM

functions a continuous flow of measurements

BTS Measurements

Reporting period

10 * Reporting period

RRIndPeriodWBTS; 200 .. 2000;

100; 400 ms


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WBTS Measurements sent to CRNC

WBTS can filter a measurement report (not sent to RNC)

only inform RNC about important load changes

reduce common NBAP signaling on IuB interface

RNC provides load thresholdand value changethreshold to WBTS

Measured

entity

Max amount of

consecutive filteredreports

Reporting period

Change threshold

Load Threshold

Report Report Report Report Time ReportReport

Parameter settings for

PtxTotal Measurement

0,5 dB

20 % of Ptx max

non-configurable:

PtxTotalLoadThreshold: 20%

PtxTotalChangeThreshold: 0.5dB

PrxTotalLoadThreshold: 20%

PrxTotalChangeThreshold: 0.2dB


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Dedicated Measurements in BTS

Transmitted Code Power

WBTS send periodic measurement reports with code power measurement results from all Radio

Links (UEs in Cell_DCH)

Depending on allocated service typeWBTS applies different reporting frequency:

CS Services &SRB:

CS Data Services:

PS Data Services:

DedicatedMeasRepPeriodWBTS; 0.5..5; 0.5; 2.5 s

DediMeasRepPeriodCSdataWBTS; 0.5..5; 0.5; 1.5 s

DediMeasRepPeriodPSdataWBTS; 0.5..5; 0.5; 0.5 s

RANPAR Combined LoadControl v1.2

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Transcript of RANPAR Combined LoadControl v1.2