04 Rn31634en40gla0 Ranpar1 Loadcontrol v1.1 Ru40

Load Control

Load Control: Module Objectives  At the end of the module you will be be able to: • Describe the the basic principles principles of Load Control Control • 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

•  Automatic Access Class Restriction

Load Control Functional Overview • LC is a cell based RRM Function, utilising cell specific:

RNC

• thresholds set by RNP, • load measurements, •  AC, PS & LC algorithms.

LC RM

PS  AC

• LC performs the function of load control

in 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

Load Control Functional Overview RRM in RNC when changed

Load change info

parameters

Load status request

AC Load change estimations

WBTS NB/RS parameters

NBAP-PRIVATE:

PS

R R In d P e r i o d o r 3GPP NBAP : COMMON MEASUREMENT

LC

measurements

Load status

Load change estimations

REPORT

measurements

estimations

PRACH load measurement

NRT load Dedicated measurement reporting

Scheduling period

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

• Automatic Access Class Restriction

NSN RRM: Power & Throughput based • DL uses Power Measurements and calculations for RRM decisions

h  DL

 P tx _ total 

=

 P   _  BTS  max tx

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

h UL

=1-

 P rx _ noise  P rx _ total 

= 1-

1  NR

defining Load = 0%  – 100%

 N 

h UL

= (1 + i ) ×  L j  j =1

 L j

1 =

1+

W  / R j

 E b / N   j 0

1 

  j

defining Little i  Slide 9

Load Estimation Methods and other cell interference 2 Load estimation methods:

Throughput based threshold

Wideband Power  based threshold

i=0 i=0.5 i=1

Own cell load factor (capacity)

UL power based load measurement P RxTotal = P Rx_Own + P Rx_Other + P Noise = P Rx_NRT + P Rx_RT + P Rx_Other + P noise = P Rx_NRT + P Rx_NC  + P Rx_SC i UL = P Rx_Other  / P Rx_Own

P Rx_Other P Rx_Own

P   – The semi-controllable interference power, consists of the powers of PS streaming users (DCH and E-DCH). Before RU10 Rx_SC 

semi-controllable traffic has not been separated from the non-controllable traffic, so for those releases it is equal to zero.

DL power based load measurement P TxTotal = P Tx_Own P Tx_Common = P Tx_NRT + P Tx_RT + P Tx_Common = P Tx_NRT + P Tx_NC + P Tx_SC P Tx_Own P Rx_Own_DL P Rx_Other_DL

i DL = P Rx_Other_DL / P Rx_Own_DL  – the power caused by the semi-controllable traffic of real-time users (PS streaming). Before RU10 semi-controllable traffic P  Tx_SC 

has not been separated from the non-controllable traffic, so for those releases it is equal to zero.

Radio Interface Load  The BTS measures the total received power ( P r x T o t a l )  and the total transmitted power (P t x T o t a l )  on cell basis  The BTS reports P r x T o t a l   & P t x T o t a l  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 PrxNoise

• System noise P r x N o i s e   is the sum of all stationary noises:

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

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

• P r x N o i s e   can vary place to place & even time to time • P r x N o i s e  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

PrxNoiseAutotuning WCEL: 0 (Off) / 1 (On)

• RNC provides Autotuning-Tool to measure u n l o a d e d s y s t e m n o i s e : 

PrxUnloaded; it adjusts PrxNoise parameter based on these measurements

UnloadedRT

• PrxTotal = PrxUnloaded when own cell considered unloaded / very low load; LRT  Unloaded RT  & LNRT  U n l o a d e d NR   T  & no EDCH users in the cell

RNC: 0..0.1; 0.01; 0.02

UnloadedNRT

U n l o a d e d RT     & Unloaded NR T are RNC parameters (default values for NRT: 1 %, RT: 2 %)

RNC: 0..0.1; 0.01; 0.01

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 P r x N o i s e M a x T u n e A b s o l u t e  

PrxNoiseMaxTuneAbsolute  WAC: 0..60; 0.5; 255 dB 255 dB: Autotuning is not limited

UL Preventive & Overload Thresholds

PrxTarget: WCEL; 0 .. 30; 0.1; 4dB PrxOffset: WCEL; 0 .. 6; 0.1; 1dB

   ]    B    d    [

  e   s    i    R   e   s    i   o    N

Overloaded Area PrxTarget [dB] + PrxOffset [dB]

Marginal Load Area

Prx Target [dB]

Feasible Load Area PrxTarget =

- 10  Log  1 - h  dB 10

load factor Range [0..1]

DL Preventive & Overload Thresholds PtxTarget: WCEL; -10 .. 50; 0.1; 40 dBm PtxOffset: WCEL; 0 .. 6; 0.1; 1dB

Cell Maximum

PtxCellMax WCEL: 0…50; 0.1; 43dBm

   d    ]   e    t   m    t    i    B   m  r   d   s  e   [    l   n  w   a   a   o   t   r   o    t   p   T    l   x   a    t    t   o    P    T

Overloaded Area Marginal Load Area

Ptx Target [dBm] + PtxOffset [dB] Ptx Target [dBm]

Feasible Load Area

load factor

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

•  Automatic Access Class Restriction

Common measurements taken & reported by WBTS • PtxTotal – Transmitted Carrier Power • Nokia Private NBAP

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

• PrxTotal – Received Total Wideband Power • Nokia Private NBAP

• REPS – Received E-DCH Power Share • Nokia Private NBAP

•  Acknowledged PRACH preambles • Nokia Private NBAP

• Provided HSDPA Bitrate • Provided HSUPA Bitrate

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

• Required Power Nokia Private part is protocol extension specified in 3GPP

WBTS Common Measurements sent to CRNC WBTS sends measurements periodically according setting of RRM parameter:

RRIndPeriod Radio Resource Indication Period WBTS; 200 .. 2000; 100; 400 ms

RADIO RESOURCE MEASUREMENT REPORT (Nokia Private part)

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

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: R R I n d P e r i o d   to provide RRM

functions a continuous flow of measurements

BTS Measurements

Reporting period RRIndPeriod WBTS; 200 .. 2000; 100; 400 ms

10 * Reporting period

WBTS Measurements sent to CRNC WBTS can filter a measurement report (not sent to RNC)  – • only inform RNC about important load changes

non-configurable: PtxTotalLoadThreshold: 20% PtxTotalChangeThreshold: 0.5dB

• reduce common NBAP signaling on IuB interface

PrxTotalChangeThreshold: 0.2dB

RNC provides load threshold  and value change threshold to WBTS Parameter settings for PtxTotal Measurement

Measured entity Max amount of consecutive filtered reports

Change threshold Reporting period Load Threshold

Report

Report

Report

Report

Report

Report

Time

0,5 dB 20 % of Ptx max

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:

DedicatedMeasReportPeriod

• CS Data Services:

DediMeasRepPeriodCSdata

• PS Data Services:

DediMeasRepPeriodPSdata

WBTS; 0.5..5; 0.5; 2.5 s

WBTS; 0.5..5; 0.5; 1.5 s

WBTS; 0.5..5; 0.5; 0.5 s

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

• Automatic Access Class Restriction

AutoACResEnabled NEW Automatic Access Class Restriction SLIDE

•

 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

RNFC; Bit 0: Received total wideband power , Bit 1: NRT scheduling queue length , Bit 2: CN overload , Bit 3: RNC overload; 0

Barred AC

•

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

- Emergency Calls

•

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

- PLMN Use

•

 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

- Security Services

•

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

- Public Utilities - Emergency Services - PLMN Staff

Automatic Access Class Restriction Parameterization

• The feature introduces following new parameters: o

RNFC: AutoACResEnabled

o

RNAC: AutoACMaxRestLevel

o

WCEL: AutoACResULOLThr

o

RNAC: AutoACIncRestHysRTWP

o

WCEL: AutoACDSACRestriction

o

RNAC: AutoACDecRestHysRTWP

o

RNAC: AutoACRLevelUpdInt

o

RNAC: AutoACIncRestHysNRTQ

o

RNAC: AutoACRestForCellPCH

o

RNAC: AutoACDecRestHysNRTQ

o

RNAC: AutoACRTrigRNCLoad

Benefits

• • • •

 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

NEW SLIDE