1 ranpar combined loadcontrol v1.0 ru40

1 © Nokia Siemens Networks RN31674EN30GLA1

Course Content

Radio Resource Management Overview

Parameter Configuration

Common Channels & Power Control

Load Control

Admission Control

Packet Scheduling

Handover Control

Resource Manager

HSDPA RRM & parameters

HSUPA RRM & parameters

HSPA+ features & parameters


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


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

• Cell Level parameters for better UL Load control

• Automatic Access Class Restriction


Load Control Functional Overview

• LC is a cell based RRM Function, utilising cell specific:

• thresholds set by RNP,

• load measurements,

• AC, PS & LC algorithms.

• LC performs the function of load controlin association with AC & PS

• LC updates 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

ACAC

PSPSRMRM

RNC


Load Control Functional Overview

RRM in RNC

LC

AC

PS

Load change estimations

Load change estimations

Scheduling period

PRACH load measurement

WBTS NB/RSNBAP-PRIVATE:RRIndPeriod or

3GPP NBAP :COMMON MEASUREMENTREPORT

Dedicated measurement reporting

parameters

parameters

measurements

estimations

when changed Load change info

Load status request

Load status

NRT load

measurements


Load Control











• DL uses Power Measurements and calculations for RRM decisions

• UL uses Power & Throughput estimations and calculations for RRM decisions

NSN RRM: Power & Throughput based

N

jjUL Li

1

)1(NRP

P

totalrx

noiserxUL

111

_

_

max_

_

BTStx

totaltxDL

P

P

defining Load = 0% – 100%

jjb

jj

NE

RWL

1

/

/1

1

0

defining Little i Slide 9

changed

changed


Load Estimation Methods and other cell interference

Throughput based

threshold

Wideband Power based

threshold

Wid

eb

an

d p

ow

er

lev

el

I tot a

l

(cov

era

ge

)

Own cell load factor (capacity)

i=0.5

i=0

i=1

2 Load estimationmethods:


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_SC

PRx_Other

iUL = PRx_Other / PRx_Own

added

PRx_SC – The semi-controllable interference power, consists of the powers of PS streaming users (DCH and E-DCH). Before RU10 semi-controllable traffic has not been separated from the non-controllable traffic, so for those releases it is equal to zero.added


DL power based load measurement

PTx_Own

PTxTotal = PTx_Own

= PTx_NRT + PTx_RT + PTx_Common

= PTx_NRT + PTx_NC+ PTx_SC

PTx_Common

Com

mon

Cha

nnel

s

PRx_Own_DL

PRx_Other_DL

iDL = PRx_Other_DL / PRx_Own_DL

PTx_SC – the power caused by the semi-controllable traffic of real-time users (PS streaming). Before RU10 semi-controllable traffic has not been separated from the non-controllable traffic, so for those releases it is equal to zero.

added

added


Radio Interface Load

The BTS measures the total received power (PrxTotal) and the total transmitted power (PtxTotal) on cell basis

The BTS reports PrxTotal & PtxTotal of 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)

AC and PS algorithms 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 & LNRT estimates

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


System Noise & PrxNoise Auto-tuning Algorithm

• System noise PrxNoise is the sum of all stationary noises:• thermal noise• interference caused by spurious emissions of other systems,• noise caused by additional equipment such as repeaters

• PrxNoise can vary place to place & even time to time

• PrxNoise setting affects the capacity of cell:• PrxNoise too low: overestimation of cell load and can lead to unnecessary call blocking

• PrxNoise too high: underestimation of cell load and can lead to overload situation

• RNC provides Autotuning-Tool to measure unloaded system noise: PrxUnloaded; it adjusts PrxNoise parameter based on these measurements

• PrxTotal = PrxUnloaded when own cell considered unloaded / very low load;LRT UnloadedRT & LNRT UnloadedNRT & no EDCH users in the cell

UnloadedRT & UnloadedNRT are RNC parameters (default values for NRT: 1 %, RT: 2 %)

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

PrxNoiseMaxTuneAbsolute WAC: 0..60; 0.5; 255 dB

255 dB: Autotuning is not limited

changed

Added/changed

UnloadedRT RNC: 0..0.1; 0.01; 0.02

UnloadedNRT RNC: 0..0.1; 0.01; 0.01

added


UL Preventive & Overload Thresholds

Prx Target [dB]

PrxTarget [dB] + PrxOffset [dB]

load factor Range [0..1]

No

ise

Ris

e [d

B] Overloaded Area

Marginal Load Area

Feasible Load Area

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

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

dBLog 110 10PrxTarget =


DL Preventive & Overload Thresholds

Ptx Target [dBm]

Ptx Target [dBm] + PtxOffset [dB]

load factor

Range [0..1]

To

tal t

ran

smit

ted

p

ow

er

Ptx T

ota

l [dB

m]

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: 0…50; 0.1; 43dBm

added


Load Control











Common measurements taken & reported by WBTS

• PtxTotal – Transmitted Carrier Power

• Nokia Private NBAP

• PtxNonHSPATransmitted Code Power of all codes not used for HSDPA


• PrxTotal – Received Total Wideband Power


• REPS – Received E-DCH Power Share


• Acknowledged PRACH preambles


• Provided HSDPA Bitrate

• Provided HSUPA Bitrate

• Required Power

RRM in RNC needs this information for Streaming mapped on HSPA(NST – Non Scheduled Transmission)

Nokia Private part is protocol extension specified in 3GPP


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


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 2L1 measurement period(= L1 Filtering) = 100 ms = 10 frames( Slide 30)

Step 3:L3 Filtering: RRI period = 400 ms( Slide 27)


L1 Filtering: Prx and Ptx Total Measurements

Prx

Tota

l/Ptx

Tota

l

Frame average measurements

Frame Prx and Ptx Total measurements

14

0// 15

1TotalPTotalP txrxtxrx

0 141 2 ...


L3 filtering: Higher layer filtering• The Measurement Filter Coefficient (k) IE indicates how filtering of the measurement

values 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 9 11 13 15 17 19 21 23 25 27 29 31 33

MeasurementsV

alu

e, d

B 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 9 11 13 15 17 19 21 23 25 27 29 31 33

Measurements

Val

ue,

dB Measured

Filtered, k = 3

Filtered, k = 7

The higher the coefficient value, the more emphasis on old filtered measurements

Examples:k=2, a=0,5 both an old filtered measurement and a new measurement have the weight of 50%K = 0 a = 1 no L3 filtering

MeasFiltCoeffMeasurement filter

coefficient kWBTS; 0 (Off); 1..14;

1; 5

Changed

MO class


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: RRIndPeriod to provide RRM functions a continuous flow of measurements

BTS Measurements

Reporting period

10 * Reporting period

RRIndPeriodWBTS; 200 .. 2000;

100; 400 ms


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 threshold and value change threshold to WBTS

Parameter settings for

PtxTotal Measurement

0,5 dB

20 % of Ptx max

The parameter

doesn’t exist


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 type WBTS applies different reporting frequency:

• CS Services & SRB:

• CS Data Services:

• PS Data Services:

DedicatedMeasReportPeriod WBTS; 0.5..5; 0.5; 2.5 s

DediMeasRepPeriodCSdata WBTS; 0.5..5; 0.5; 1.5 s

DediMeasRepPeriodPSdata WBTS; 0.5..5; 0.5; 0.5 s

Parameter name corrected


Load Control











Cell Level parameters for better UL Load control

• This feature introduces a new WAC (WCEL Admission Control) radio network object for storing the UL load control AC and a few state transition control parameters in the RNW database on RNC

• Some currently RNC level parameters are changed to cell level

• The feature is a part of basic software and it doesn’t need activation

• Enables cell level tuning of mass event cells such as stadiums

• Cell based tuning is needed especially in certain events when load of the cell is known to be high. Tuning helps to better cope with high UL load

• The operators can also control state transitions differently in different frequency layers

RNC

WBTS IOU

IUPS

IUR

ADJD

WCEL

ADJG

ADJI

ADJL

CBCI

CMOB

COCO

FMCS

HOPG

FMCI

IPNB

IUCS

ADJS IPQM

IUCSIPVBTSVCEL

TQM

WRAB

WLCSE

WSG

WSMLC

FMCG

HOPI

HOPL

HOPS

WANE

IUPSIP

PFL

WAC

RNC

WBTS IOU

IUPS

IUR

ADJD

WCEL

ADJG

ADJI

ADJL

CBCI

CMOB

COCO

FMCS

HOPG

FMCI

IPNB

IUCS

ADJS IPQM

IUCSIPVBTSVCEL

TQM

WRAB

WLCSE

WSG

WSMLC

FMCG

HOPI

HOPL

HOPS

WANE

IUPSIP

PFL

WAC

NEW

SLIDE

Benefits Benefits


Cell Level parameters for better UL Load control

The following parameters are moved from RNC and WCEL objects to the new WAC object:

• HSDPAInitialBRULStrNRT

• HSDPAMinBRULStrNRT

• HSDPAinitialBitrateUL

• HSDPAminallowedBitrateUL

• TrafVolPendingTimeDL

• TrafVolPendingTimeUL

• TrafVolThresholdULLow

• PrxNoiseMaxTuneAbsolute

• WaitTimeRRC parameter structure

•MACdflowthroughputAveWin,

•MACdflowutilRelThr ,

• MACdflowutilTimetoTrigger

• EDCHMACdFlowThroughputAveWin,

• EDCHMACdFlowThroughputRelThr,

• EDCHMACdFlowThroughputTimetoTrigger

• InactNonCPCBatOptT

• InactNonCPCNoBatOptT

• InactCPCBatOptT

• InactCPCNoBatOptT

• DCHUtilRelThrDL

• DCHUtilRelAveWin

• DCHUtilRelTimeToTrigger

• DCHUtilRelThrUL

• InactivityTimerDownlinkDCH

• InactivityTimerUplinkDCH

• UL_DL_activation_timer

• MSActivitySupervision

• InactHSRACH

• HSDPAMaxBitrateUL

NEW

SLIDE


Load Control











Automatic Access Class Restriction

• Automatic Access Class Restriction allows limiting access to the network in overload conditions for a number of UE to reduce control plane and user plane traffic

• The access class for every UE is a randomly allocated digit from 0 to 9, stored in the SIM/USIM

• The feature sets automatically and dynamically a number of the access classes to a barring state (by default all the UE access classes 0,...,9 are allowed for accessing the network) if severe overload conditions occur

• The number of access classes is automatically increased or decreased as the overload condition continues or respectively relaxes

• Barred Access Classes can be cycled to avoid specific subscribers from being barred for long periods of time

• Individual Access Classes can be barred by listing them within SIB3

• It returns the system to normal state once the overload conditions are over

• Access Class 10 is reserved to indicates whether or not network access for Emergency Calls is allowed for UEs with access classes 0 to 9 or an without IMSI

• The feature can be activated by turning on the Long Term ON/OFF license key Automatic Access Class Restriction and RNC level radio network planning parameter AutoACResEnabled

Public Subscribers

- PLMN Use

- Security Services

- Public Utilities

- PLMN Staff

- Emergency Calls

- Emergency Services

Barred AC

NEW

SLIDE

AutoACResEnabledRNFC; Bit 0: Received total wideband power , Bit 1: NRT scheduling queue

length , Bit 2: CN overload , Bit 3: RNC overload; 0


Automatic Access Class Restriction

• The feature introduces following new parameters:o RNFC: AutoACResEnabled

o WCEL: AutoACResULOLThr

o WCEL: AutoACDSACRestriction

o RNAC: AutoACRLevelUpdInt

o RNAC: AutoACRestForCellPCH

o RNAC: AutoACRTrigRNCLoad

• A smooth, automatic overload control in UTRAN

• Avoidance of dramatic overload toggling at the core network

• Increasing the successful traffic share in case of core network overload

• Management parameters are replaced by an automatic functionality (OPEX savings)

• Limitation to minimum of the amount of subscribers affected in case overload condition occurrence

ParameterizationParameterization

o RNAC: AutoACMaxRestLevel

o RNAC: AutoACIncRestHysRTWP

o RNAC: AutoACDecRestHysRTWP

o RNAC: AutoACIncRestHysNRTQ

o RNAC: AutoACDecRestHysNRTQ

Benefits Benefits

NEW

SLIDE

1 ranpar combined loadcontrol v1.0 ru40

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