
Course Objectives

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

• Describe the criteria for RRC connection state change and their relationship to the packet scheduler

• Identify the transport channels used for NRT traffic

• Explain how packet scheduler influences the controllable load

• Explain the capacity request procedure

• Identify the reasons for TFCS modification

• Name and describe the main RAN parameters related to packet scheduler


Packet Scheduling• Overview

• Packet Transfer States & Parameters• Bitrate Allocation• Capacity Request & Traffic Volume Measurements • Channel Type Selection• Processing a Capacity Request• Packet Scheduler Interruption Timer

• Bitrate Upgrade

• Overload Control

• Dynamic Link Optimisation (DyLo)

• Activation Time optimization


Why Packet Scheduling?

Load(~ Power)

time

PlannedLoad/PowerTargetFree Capacity

Non-Controllable Load• real time traffic• interference from other cell users• noise

• Suitable for controllable load (=best effort NRT)• Requires fast resource allocation


Nokia Packet Scheduler – main features


Packet Scheduling Principles

Cell_FACH Cell_DCH Cell_FACH

Uplink DCH

Downlink DCH

non-GBR RB data transfer active Radio link & Iub AAL2 setupnon-GBR RB inactivity timer running Radio link & Iub AAL2 release

RRC state


Cell_FACH Cell_DCH Cell_FACH

Uplink DCHs

Downlink DCHs

GBR RB Radio link & Iub AAL2 setupnon-GBR RB data transfer active Radio Link & Iub AAL2 modificationnon-GBR RB inactivity timer running Radio link & Iub AAL2 release

RRC state

Packet Scheduling Principles


Packet Scheduling Principles• Packet Scheduler switches between common channels (FACH/RACH =

low capacity) and dedicated channels (DCH = higher bit rates)

• Packet Scheduler allocates to RABs temporarily dedicated channels with a set of maximum bit rates

• For instance within an allocation for 384kbit/s, the instantaneous bit rate can be {0, 8, 16, 32, 64, 128, 384} kbit/s

• Packet Scheduler allocates DCH based on Capacity Requests• A Capacity Request (Nokia term) is triggered based on traffic

volume measurement info: the sender (UE or RNC) has data in buffer and no sufficient dedicated channel

• Packet Scheduler releases DCH upon inactivity

• Packet Scheduler re-schedules continuously DCH to serve all requests equally, and take into account changes in non-controllable load


Packet Scheduling

Power/ Load

time

non-controllable loadi.e. RT Traffic

controllable loadi.e. non RT Traffic

PtxTotal (variable) PrxTotal

PtxNrt PrxNrt

PtxTarget PrxTarget

PtxOffset PrxOffset

PtxTargetBTS PrxTargetBTS

overload

DesiredPrx/PtxValues

PtxRt PrxRt


RAN1.5.1RAN1.5.1RAN1.5.1 RAN1.5.2ED2

RAN1.5.2EDRAN1.5.2ED22 RAN04RAN04RAN04 RAN05RAN05RAN05

Supported Radio Bearers in RANFuture itemsFutureFuture itemsitems

AMR 12.2

AMR = Conversational CS speechTransparent CS data = Conversational CS dataUDI = Unrestricted Digital Information (Video Call)Non-transparent CS data = Streaming CS dataNRT PS data = Interactive/Background PS data

RBs of higher uplink bit rates than 64 kbit/s not end-to-end tested, up to UE availability. Delivery 6 monthsfrom a stabile UE for the tests at earliest.

Streaming PS data RBs are subject to changes and restrictions according to 3GPP TS 25.993 and TS 34.108. Delivery 6 months from a stabile UE for the tests at earliest. 256 for DL only.

AMR 12.2Transparent CS data (UDI) 64Transparent CS data (UDI) 64Non-transparent CS data 14.4, 57.6Non-transparent CS data 14.4, 57.6NRT PS data 64, 128, 384NRT PS data 64, 128, 384

Non-transparent CS data 14.4Non-transparent CS data 14.4NRT PS data 8, 16, 32NRT PS data 8, 16, 32Streaming PS data 8, 16, 32, 64, 128, 256 (DL)Streaming PS data 8, 16, 32, 64, 128, 256 (DL)

NRT PS data 256NRT PS data 256

Lower AMR speech ratesLower AMR speech rates

WB-AMR speechratesWB-AMR speechrates

ConversationalPS QoSConversationalPS QoS




• Bitrate Upgrade





URA_PCH

CELL_DCH CELL_FACH

CELL_PCH

UTRA RRC Connected Mode

Idle Mode

URA_PCH

CELL_DCH CELL_FACH

CELL_PCH

Cell selectionCell re-selection

Dedicated resourcesallocated (DCH)Tx and Rx mode

Common resourcesallocated (RACH-FACH)

Tx and Rx mode

UE in DRX modediscontinous receiption

UE in DRX modediscontinous reception

RRC State Machine

IuB

Cell Update, UL Tx

UL/DL activation timer

Traffic volumeInactivity Timer

UL Tx

Frequent cell updates


PS Connection Establishment

RNCUE SGSN

RRC Connection Establishment (SRB)

MM & CC (e.g. PDP Context Activation)

RAB Assignment RequestTraffic Volume Parameters

determination

Measurement Control [Traffic Volume Measurements]

CELL_DCH

Start• RB_InactivityTimer• SignallingLinkInactivityTimer

RB_InactivityTimerexpiry

Capacity Request?

DCH for NRT RB(s) allocation

no

yes

yes

SignallingLinkInactivityTimeexpiry

CELL_FACH


Transition from CELL_DCH to CELL_FACH

RNCUECELL_DCH Node B

PDU Transport on the DCH/DPCH

All data is sent andRLC-U buffer is empty

Inactivity detected Start

InactivityTimerUplinkDCHInactivityTimerDownlinkDCH

Radio Bearer Reconfiguration

Radio Bearer Reconfiguration Complete

ExpiryCELL_FACH

L2 configuration

Radio Link Release

StartMAC: Inactivity detected



Transition from CELL_FACH/CELL_PCH to Idle

StartMAC: Inactivity detected


UECELL_FACH

CELL_FACH Cell Update

Cell UpdateCell Update Confirm

URA_PCH

MaxCellReselectionsCellReselectionObservingTimeandMaxPeriodicalCellUpdates

Start

Expiry

Expiry

RNC

analog inCELL_PCH

URA Update

URA UpdateURA Update Confirm

Inactivity detected

Transition to URA_PCH

MSActivitySupervision

URA_PCH

RRC-IDLE

CELL_PCH Radio Bearer Reconfiguration


Transition from CELL_FACH to CELL_DCH

RNCUECELL_FACH Node B

UL & DL packet scheduling


Measurement Report (Traffic Volume Event e4a)

CELL_DCH

Radio Link Setup


UE initiated


Transition from CELL_FACH to CELL_DCH

RNCUECELL_FACH Node B

DL capacity need isdetected by MAC


CELL_DCH

Radio Link Setup


RNC initiated

Channel type selection-> DCH

UL & DLpacket scheduling


Nokia Parameters

• RB_InactivityTimer• The timer is set after a DCH for a signaling link is allocated in RRC connection setup

phase. The timer is reset when any DL/UL activity detected (i.e. capacity request received from the MS or RNC's MAC-c). In expiry of the timer, the state transition from CELL_DCH to CELL_FACH is initiated when also the SignallingLinkInactivityTimer has expired.default value: 2s; range: 0 ... 20 s; step 0.5 s

• SignallingLinkInactivityTimer• The timer is used for inactivity detection of the signaling link in CELL_DCH and

CELL_FACH states. The timer is set after inactivity of the signaling link is detected and reset when any activity detected. In expiry of the timer, a state transition from CELL_DCH to CELL_FACH (or from CELL_FACH to CELL_PCH) state is initiated when also the corresponding RB inactivity timer(s) expired. default value: 2s; range: 0 ... 20 s; step 0.5 s


Nokia Parameters

• InactivityTimerUplinkDCH• The time indicating how long the radio and transmission resources are reserved after

silence detection on uplink DCH before release procedures

• range: 8 kbps: 5 s, 16 kbps: 5 s, 32 kbps: 5 s, 64 kbps: 3 s, 128 kbps: 2 s, 256 kbps: 2 s, 320 kbps: 2 s, 384 kbps: 2 s

• InactivityTimerDownlinkDCH• The time indicating how long the radio and transmission resources are reserved after

silence detection on downlink DCH before release procedures

• range: 8 kbps: 5 s, 16 kbps: 5 s, 32 kbps: 5 s, 64 kbps: 3 s, 128 kbps: 2 s, 256 kbps: 2 s, 320 kbps: 2 s, 384 kbps: 2 s

• Recommendation is to use 20 s for all services


Nokia Parameters

• UL/DL activation timer• This timer is set when the MS is transferred to CELL_FACH state due to inactivity, or MS

inactivity is detected in CELL_FACH state (CELL_FACH-> IDLE)default value: : 2s; Recommendation is to set this to 10s

• range: 50 ... 10000 ms; step 50 ms

• MSActivitySupervision• The RNC supervises traffic of MS with only NRT RABs. When no data transfer is

performed during the defined time period, the RNC asks SGSN to release Iu

• default value: 30 min; range: 0 ... 1440 min; step 1 min


Nokia Parameters• CellReselectionObservingTime

• Detailed description: The timer is set when first Cell Update message due to 'cell reselection' is received while MS is in CELL_FACH or CELL_PCH state. In expiry of the timer, the counter MaxCellReselections is reset

• default value: 10s; range: 0 ... 60 s; step 1 s

• MaxCellReselections• The number of Cell Reselections in CELL_FACH or CELL_PCH state during

CellReselectionObservingTime before transition to URA_PCH state

• default value: 3 times; This is set to 0 in RAN1.5.2ED2, cannot be changedrange: 0 ... 100 times; step 1 times

• MaxPeriodicalCellUpdates• Counter for a number of Periodical Cell Updates in CELL_FACH or CELL_PCH state

before transition to URA_PCH state

• default value: 1 time; range: 0 ... 10 times; step 1 times


IdleMode

Cell_FACH

• Inactivity detection of NRT RB

• Release of RT RB

• Cell reselection (moving UE)

• Periodic cell update (stationary UE)

• Paging response (DL data/ signalling)

• UL Access (UL data/signalling)

• URA reselection Periodic URA update (stationary MS)

• Periodic URA update (stationary MS)

• Paging response (DL data / signalling)

• UL Access (UL data / signalling) Cell_

PCH

• Activity supervision• Completion of Cell Update procedure

• Setup of RT/NRT RB• RAB reconfiguration • DCH Up or Downgrade• Bit rate reduction due to load reasons

Cell_DCH

• CN originated paging (MT Call)• Random Access (MO Call)

URA_PCH

• Completion of URA Update procedure

• Max. number of periodic cell updates in Cell_FACH / Cell_PCH exceeded

• UL/DL data or signalling

• RT RB setup

RRC Connection Release

Summary




• Bitrate Upgrade





Decrease loadingIncrease loading

Bit rate allocation algorithm

PrxTotal < PrxTarget NOYES

PrxTotal <PrxTarget + PrxOffsetYES

Allocate bit rates

end

NO

Calculate PrxAllowed

Bit Rate Allocation - Overview

nrtrxncrxtotalrx PPP ___ +=

non-controllable power

controllable power

inactivertrxinactivenrtrx

totalrxettrxallowedrx

PP

PPP

____

_arg__

−−

−=

estimated received power of admitted RT bearers still in the in the establishment phase

estimated received power of RT admitted but currently inactive bearers

Example: UL


Packet Scheduling and Load Control

RNCRadio Resource Indication

Node B

Radio Resource Indication



RRIndPeriod

Packet Scheduler decision frequency: SchedulingPeriod

nntPtPtP

P totalrxtotalrxtotalrxtotalrx

))1((...)1()( ____

−−++−+=

n = PSAveragingWindowSize

Averaged PrxTotal:

Averaged PtxTotal: (analog to averaged PrxTotal)

time


• PSAveragingWindowSize• The parameter defines how many PrxTotal/PtxTotal measurements, which are received

in the NBAP: RADIO RESOURCE INDICATION - messages, are included in the sliding window averaging

• default value: 5; range: 1 ... 20 , step 1

Individual Measurement Values 4 1 3 5 7 10 6Averaging Window Size = 3 5.0 7.3 7.7Averaging Window Size = 4 4.0 6.3 7.0Averaging Window Size = 5 4.0 5.2 6.2

Parameters for Packet Scheduling


Parameters for Packet Scheduling• MinAllowedBitRateUL

• This parameter defines the minimum allowed bit rate in uplink that can be allocated by the PS

• default value: 16 kbps; range: 8 kbps, 16 kbps, 32 kbps, 64 kbps, 128 kbps, 256 kbps, 320 kbps, 384 kbps

• MinAllowedBitRateDL• This parameter defines the minimum allowed bit rate in downlink that can be allocated

by the PS

• default value: 32 kbps; range: 8 kbps, 16 kbps, 32 kbps, 64 kbps, 128 kbps, 256 kbps, 320 kbps, 384 kbps

• In RAN1.5.2 MinAllowerBitrateUL is always 64 kbits/s and MinallowedbitrateDLcan be 64,128 or 384 kbits/s


Parameters for Packet Scheduling• SchedulingPeriod

• This parameter defines how often the packet scheduler makes scheduling decisions, and when it can start doing allocations.default value: 500 ms; range: 100 ... 2000 ms, step 100 ms

• Note: The value of the scheduling period should be set longer than (or equal) the Radio Resource Indication period (RRIndPeriod) in order to have the latest load information available for packet scheduling.

• RRIndPeriod• The parameter defines the reporting period of the Radio Resource Indication messages,

which are used for cell based load measurements

• default value: 500 ms; range: 0 ... 2000 ms, step 100 ms.

• With the Radio Resource Indication message the BTS reports periodically the total uplink interference power of the cells and the total transmitted power of the cell and RACH load (average number of RACH received per radio frame).




• Bitrate Upgrade





UL Traffic Volume Based RRC State TransitionReporting event:

4A: Transport Channel Traffic Volume becomes larger than an absolute threshold

time

Transport ChannelTraffic Volume

(= UE Buffer Load)

Thresholds

4A 4A 4A

RNCUEMeasurement Report (Traffic Volume Event)

UE in CELL_FACH: TrafVolThresholdULLow (128 Bytes)UE in CELL_DCH: TrafVolThresholdULHigh (4096 Bytes)

Measurement Report (Traffic Volume Event)TrafVolPendingTimeUL (2s)

4A 4AMeasurement

report hasinformation about

currentUE buffer load


NRT bit rate allocation method

• The traffic volume measurement reports are classified into the following three types:

1. Initial request for low bit rate (UL/DL); when• The NRT RB in question has no previous DCH allocation• RLC buffer payload < TrafVolThresholdDLHigh or TrafVolThresholdULHigh• Low bitrate means minimum bitrate

2. Initial request for high bit rate (UL/DL); when• The NRT RB in question has no previous DCH allocation• RLC buffer payload => TrafVolThresholdDLHigh or TrafVolThresholdULHigh

3. Upgrade request for high bit rate (DL); when• The NRT RB in question has a low bit rate DCH allocation• RLC buffer payload => TrafVolThresholdDLHigh or TrafVolThresholdULHigh


Uplink traffic volume measurements

Traffic volume measurement not triggered

RLC

buff

er p

aylo

adRL

C bu

ffer

pay

load

(tra

nspo

rt c

hann

el t

raff

ic v

olum

e)(t

rans

port

cha

nnel

tra

ffic

vol

ume)

UL data transmission on RACH in

CELL_FACH state

UL data transmission on DCH in CELL_DCH

state

TrafVolThresholdULLow (Cell parameter)

4A

TrafVolThresholdULHigh (RNC parameter)

Traffic volume measurement triggered, request for high bit rate4A


Downlink traffic volume measurements

RLC

buff

er p

aylo

adRL

C bu

ffer

pay

load

(tra

nspo

rt c

hann

el t

raff

ic v

olum

e)(t

rans

port

cha

nnel

tra

ffic

vol

ume)

TrafVolThresholdDLLow (Cell parameter)

TrafVolThresholdDLHigh (RNC parameter)

DL data transmission on FACH in

CELL_FACH state

DL data transmission on DCH in CELL_DCH

state

Traffic volume measurement not triggered

Traffic volume measurement triggered, request for low bit rate

Traffic volume measurement triggered, request for high bit rate


• TrafVolThresholdULLow• This parameter defines, in bytes, the threshold of data in the RLC buffer of RB that

triggers the uplink traffic volume measurement report, when the UE is in Cell_FACH state.

• Otherwise, UE sends data on RACH.

• This parameter is sent to the UE using an RRC: MEASUREMENT CONTROL message.

• default value: 128 bytes; range: 8 bytes, 16 bytes, 32 bytes, 64 bytes, 128 bytes, 256 bytes, 512 bytes, 1024 bytes (1 KB)

• TrafVolThresholdULHigh• The parameter defines the threshold of data in RLC buffer of RB in bytes.

• The parameter is sent to the UE using the RRC: MEASUREMENT CONTROL message.

• default value: 4096 bytes; range: 8 bytes, 16 bytes, 32 bytes, 64 bytes, 128 bytes, 256 bytes, 512 bytes, 1024 bytes (1 KB), 2048 bytes (2 KB), 3072 bytes (3 KB), 4096 bytes (4 KB)

UL Traffic Volume Based RRC State Transition


• TrafVolPendingTimeUL• This parameter indicates the period of time, in seconds, during which it is forbidden to

send any new traffic volume measurement reports with the same measurement ID, even if the triggering condition is fulfilled again

• Parameter is sent to UE using an RRC: MEASUREMENT CONTROL message.

• default value: 2000 ms; range: 250 ms, 500 ms, 1000 ms, 2000 ms, 4000 ms, 8000 ms, 16000 ms

• Note: The same value should be set in all cells within a Node B

• TrafVolTimeToTriggerUL• This parameter defines, in ms, the period of time between the timing of event detection

and the timing of sending a traffic volume measurement report.

• This parameter is sent to the UE using an RRC: MEASUREMENT CONTROL message.

• default value: 0 ms; range: 0 ms, 10 ms, 20 ms, 40 ms, 60 ms, 80 ms, 100 ms, 120 ms, 160 ms, 200 ms, 240 ms, 320 ms, 640 ms, 1280 ms, 2560 ms, 5000 ms

UL Traffic Volume Based RRC State Transition


• TrafVolThresholdDLLow• This parameter defines, in bytes, the threshold of data in the RLC buffer of RB that

triggers the downlink traffic volume measurement report (capacity request) on MAC, when UE is in Cell_FACH state. Otherwise, RNC sends data on FACH

• default value: 128 bytes; range: 0 bytes, 8 bytes, 16 bytes, 32 bytes, 64 bytes, 128 bytes, 256 bytes, 512 bytes, 1024 bytes (1 KB)

• TrafVolThresholdDLHigh• This parameter defines the threshold of data in the RLC buffer of RB in bytes which

triggers downlink traffic volume measurement report (capacity request) on MAC, when UE is in a Cell_DCH state and the initial bit rate DCH is allocated for the radio bearer

• default value: 4096 bytes; range: 0 bytes, 8 bytes, 16 bytes, 32 bytes, 64 bytes, 128 bytes, 256 bytes, 512 bytes, 1024 bytes (1 KB), 2048 bytes (2 KB), 3072 bytes (3 KB), 4096 bytes (4 KB)

DL Traffic Volume Based RRC State Transition


• TrafVolTimeToTriggerDL• This parameter defines, in ms, the period of time between the timing of event detection

and the timing of sending a downlink capacity request

• default value: 0 ms; range: 0 ms, 10 ms, 20 ms, 40 ms, 60 ms, 80 ms, 100 ms, 120 ms, 160 ms, 200 ms, 240 ms, 320 ms, 640 ms, 1280 ms, 2560 ms, 5000 ms

• TrafVolPendingTimeDL• This parameter indicates the period of time, in ms, during which it is forbidden to send

any new downlink capacity requests with the same RB id, even if the triggering condition is fulfilled again

• default value: 2000 ms; range: 250 ms, 500 ms, 1000 ms, 2000 ms, 4000 ms, 8000 ms, 16000 ms

DL Traffic Volume Based RRC State Transition


RN23 Monitoring ResultsRN23 Monitoring Results

Fact Recaped:Fact Recaped:

Effective Date & Time: 12 April 2006 @ 1900hrsEffective Date & Time: 12 April 2006 @ 1900hrs

Parameter changed: RNC Parameter changed: RNC PS Tab PS Tab Traffic Volume Traffic Volume Measurement High Threshold Measurement High Threshold Downlink = 1024bytes to Downlink = 1024bytes to

4096bytes4096bytes


RN23 – DUR_PS_BACKG_XXX_DL_IN_SRNC (384/128/64kbps)


RN23 – DUR_PS_BACKG_XXX_DL_IN_SRNC (384/128/64kbps)

Before ChangeBefore Change After ChangeAfter Change


Counters MonitoredCounters Monitored


DUR_PS_BACKG_XXX_DL_IN_SRNC (M1002C233-37)


Example SignallingExample Signalling


E.g. Signalling – Emome WAP (TrafVolThresholdDL High = 1024bytes)

Initial & Min. Bitrate = 128kbps assigned

SF16 = 128kbps

Initial & Min. Bitrate = 128kbps Initial & Min. Bitrate = 128kbps assigned assigned

SF16 = 128kbpsSF16 = 128kbps

DL Capacity Request Radio Bearer Reconfig to upgrade to Max. Bitrate = 384kbps

SF8 = 384kbps

DL Capacity Request DL Capacity Request Radio Radio Bearer Reconfig to upgrade to Bearer Reconfig to upgrade to Max. Bitrate Max. Bitrate = 384kbps= 384kbps

SF8 = 384kbpsSF8 = 384kbpsTypically 2 stages of Radio Bearer Reconfiguration: Init & Min Max Bitrate Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh ( DL Capacity Request triggered)

Typically 2 stages of Radio Bearer Typically 2 stages of Radio Bearer Reconfiguration: Init & Min Reconfiguration: Init & Min Max Bitrate Max Bitrate Upgrade if data amount arriving at RNC RLC Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh (Buffer > TrafVolThresholdDLHigh ( DL DL Capacity Request triggered)Capacity Request triggered)


E.g. Signalling – Emome WAP (TrafVolThresholdDL High = 4096bytes)


SF16 = 128kbps

Initial & Min. Bitrate = 128kbps Initial & Min. Bitrate = 128kbps assigned assigned


No DL Capacity Request to upgrade Radio Bearer, RB remains at Init & Min Bitrate = 128kbps

SF16 = 128kbps

No DL Capacity Request to No DL Capacity Request to upgrade Raupgrade Radio Bearer, RB dio Bearer, RB remains at Init & Min Bitrate remains at Init & Min Bitrate = = 128kbps128kbps


Typically 2 stages of Radio Bearer Reconfiguration: Init & Min Max Bitrate Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh ( DL Capacity Request triggered).

In this case, WAP surfing is not assigned max bitrate of 384kbps due to the low byte size of Emome WAP pages.

Typically 2 stages of Radio Bearer Reconfiguration: Typically 2 stages of Radio Bearer Reconfiguration: Init & Min Init & Min Max Bitrate Upgrade if data amount Max Bitrate Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh arriving at RNC RLC Buffer > TrafVolThresholdDLHigh (( DL Capacity Request triggered).DL Capacity Request triggered).

In this case, WAP surfing is not assigned max bitrate In this case, WAP surfing is not assigned max bitrate of 384kbps due to the low byte size of Emome WAP of 384kbps due to the low byte size of Emome WAP pages.pages.


E.g. Signalling – Nemo FTP (TrafVolThresholdDL High = 1024bytes)


SF16 = 128kbps

Initial & Min. Bitrate = 128kbps assigned Initial & Min. Bitrate = 128kbps assigned



SF8 = 384kbps

DL Capacity Request DL Capacity Request Radio Bearer Radio Bearer Reconfig to upgrade to Max. Bitrate Reconfig to upgrade to Max. Bitrate = = 384kbps384kbps


Typically 2 stages of Radio Bearer Reconfiguration: Init & Min Max Bitrate Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh (1024bytes) ( DL Capacity Request triggered)

Typically 2 stages of Radio Bearer Typically 2 stages of Radio Bearer Reconfiguration: Init & Min Reconfiguration: Init & Min Max Bitrate Max Bitrate Upgrade if data amount arriving at RNC RLC Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh (1024bytes) Buffer > TrafVolThresholdDLHigh (1024bytes) (( DL Capacity Request triggered)DL Capacity Request triggered)


E.g. Signalling – Nemo FTP (TrafVolThresholdDL High = 4096bytes)


SF16 = 128kbps

Initial & Min. Bitrate = 128kbps assigned Initial & Min. Bitrate = 128kbps assigned



SF8 = 384kbps

DL Capacity Request DL Capacity Request Radio Bearer Radio Bearer Reconfig to upgrade to Max. Bitrate Reconfig to upgrade to Max. Bitrate = = 384kbps384kbps


Typically 2 stages of Radio Bearer Reconfiguration: Init & Min Max Bitrate Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh (1024bytes) ( DL Capacity Request triggered)

Typically 2 stages of Radio Bearer Typically 2 stages of Radio Bearer Reconfiguration: Init & Min Reconfiguration: Init & Min Max Bitrate Max Bitrate Upgrade if data amount arriving at RNC RLC Upgrade if data amount arriving at RNC RLC Buffer > TrafVolThresholdDLHigh (1024bytes) Buffer > TrafVolThresholdDLHigh (1024bytes) (( DL Capacity Request triggered)DL Capacity Request triggered)




• Bitrate Upgrade





The channel selection procedure the following parameters are needed:

• Downlink traffic volume measurement low threshold (TrafVolThresholdDLLow)

• Maximum allowed total data amount on FACH (FachDataAllowedTotal)

• Threshold for RACH load (RachLoadThresholdCCH)

• Margin for RACH load (RachLoadMarginCCH)

• Threshold for FACH load (FachLoadThresholdCCH)

• Margin for FACH load (FachLoadMarginCCH)

• Threshold for total downlink transmission power (PtxThresholdCCH)

• Margin for total downlink transmission power (PtxMarginCCH)

(A) Maximum allowed user data amount on FACH exceeded

(B) Maximum allowed total data amount on FACH exceeded

(C) FACH in overload(D) FACH usage forbidden by PS

Request DCH from PSInitial transmission

on FACH

Channel Type SelectionChannel type selection

(A)

(B)

(C)

(D)

end

No

No

No

No

Yes

Yes

Yes

Yes


DL Traffic Type Selection

time

FACH overload FachLoadThresholdCCH/RachLoadThresholdCCH

FachLoadMarginCCH/RachLoadMarginCCH

FACH in overload

FACH usage ok

time

FACH forbidden

FACH in overload

FACH usage ok

PtxThresholdCCH(relative to PtxTarget

PtxMarginCCH

Load

Power / Load


• FachDataAllowedTotal• This parameter defines the maximum amount of user data in all RLC buffers that can be

transmitted at any given time on FACH (FACH is already selected)

• default value: 1024 bytes; range: 0 bytes, 8 bytes, 16 bytes, 32 bytes, 64 bytes, 128 bytes, 256 bytes, 512 bytes, 1024 bytes (1 KB), 1536 bytes, 2048 bytes (2 KB), 3072 bytes (3 KB), 4096 bytes (4 KB), 6144 bytes (6 KB), 8192 bytes (8 KB), 12288 bytes (12 KB), 16384 bytes (16 KB), 24576 bytes (24 KB), 32768 bytes (32 KB)

FACH/RACH Load Related Parameters


• RachLoadThresholdCCH• The threshold for the total load of RACH channel for uplink channel type selection. If

the threshold is exceeded, DCH is allocated

• default value: 75%; range: 0 ... 100%; step 1%

• RachLoadMarginCCH• The margin for the RACH load for downlink channel type selection

• When the measured load is below the set threshold by this margin, FACH usage is possible




• FachLoadThresholdCCH• The threshold for the total load of SCCPCH (FACH/PCH) channel for downlink channel

type selection. If the threshold is exceeded, DCH is allocated


• FachLoadMarginCCH• The margin for the total load of SCCPCH (FACH/PCH) for downlink channel type

selection. When the measured load is below the threshold by at least this margin, FACH usage is possible




• PtxThresholdCCH• This is the threshold for the total downlink transmission power for downlink channel

type selection

• If the threshold is exceeded, a DCH is allocated. Assumption here is that a DCH is more efficient than a FACH, due to fast power control.

• Relative to PtxTarget

• default value: -1 dB; range: -5 ... 0 dB; step 0.1 dB

• PtxMarginCCH• The margin for the total downlink transmission power for downlink channel type

selection

• When the measured load is below the threshold by this margin, FACH usage is possible

• default value: 0.5dB; range: 0 ... 2 dB; step 0.1 dB





• Bitrate Upgrade





new capacity request for a change in data

rate?

No

Yes

New capacity request

No

Modify the content type of the original capacity request in a queue

Delete the new capacity request

YesDelete the request

Start scheduling process(A) Capacity request from UE already in a queue?

(B) Is new capacity request same as original?

(A)

(B)

CrQueuingTimeULCrQueuingTimeDL

based on• Arrival time• Bearer class• Traffic handling priority

Processing of Capacity Request

CrHandlingPolicyULCrHandlingPolicyDL


• CrQueuingTimeUL• This parameter defines how long an uplink capacity request can stay in the

queue before it is permanently removed

• default value: 4 sec; range: 1 ... 30 sec; step 1 sec

• Note: This value should be the same as TrafVolPendingTimeUL

TrafVolPendingTimeUL• This parameter indicates the period of time, in seconds, during which it is

forbidden to send any new traffic volume measurement reports with the same measurement ID, even if the triggering condition is fulfilled again. Parameter is sent to UE using an RRC: SYSTEM INFORMATION or an RRC: MEASUREMENT CONTROL message

• default value 2000 ms; range: 250 ms, 500 ms, 1000 ms, 2000 ms, 4000 ms, 8000 ms, 16000 ms

• Note: This value should be set the same in all cells within a BTS



• CrQueuingTimeDL• This parameter defines how long an downlink capacity request can stay in the

queue before it is permanently removed.default value:4 sec; range: 1 ... 30 sec; step 1 sec

• Note: This value should be the same as TrafVolPendingTimeDL

• TrafVolPendingTimeDL• This parameter indicates the period of time, in milliseconds, during which it is

forbidden to send any new downlink capacity requests with the same RB id, even if the triggering condition is fulfilled again.default value: 2000 ms; range: 250 ms, 500 ms, 1000 ms, 2000 ms, 4000 ms, 8000 ms, 16000 ms

• Note: This value should be set the same in all cells within a BTS



• CrHandlingPolicyUL• This parameter defines the criteria which are taken into account when the

capacity requests are arranged for DCH scheduling

• default value: 2 range: 1 (arrival time only), 2 (arrival time and bearer class), 3 (arrival time, bearer class and traffic handling priority)

CrHandlingPolicyDL• This parameter defines the criteria which are taken into account when the

capacity requests are arranged for DCH scheduling

• default value: 2 range: 1 (arrival time only), 2 (arrival time and bearer class), 3 (arrival time, bearer class and traffic handling priority)





• Bitrate Upgrade





Any CRs in queueStart from

CR #1

Estimate PrxTotalNew andPrxNrtNew

Bit rate = MinAllowedBitRate

Increase loading

(A) PtxTotalNew < PtxTarget ANDPtxTotalChange < DeltaPtxMaxUpPtxNrtNew < PtxAllowed

(A)

End

Yes

No

Bitrate Upgrade Process

No

changetotaltxtotaltxnewtotaltx PPP _____ +=

Example: DL

Yesmore CRsin queue

Move toNext CR inQueue

HigherAllowed Bitrates

Move toNext higher

bitrate

NoYes


128 (1) 256 (1) 384 (1)

Step 3

PrxTarget

No higher bit rateavailable, allocationaccording to step 3

Step 1 Step 2

128 (1)

128 (2)256 (1)

128 (2)

256 (1)

256 (2)

384 (1)

256 (2)PrxTarget

Step 1 Step 2 Step 3 Step 4

128 (1)

Step 5

Target exceeded,allocation according

to step 4

case 1: 1 CR in queue

case 2: 2 CRs in queue

128 (1)128 (2)

128 (3)

256 (1)

256 (2)

PrxTarget


128 (1)

Step 5

128 (2)128 (1)

128 (3)128 (2)

256 (1)

128 (3)


to step 4

128 (1)128 (2)

128 (3)

PrxTarget


128 (1)

Step 5

128 (2)128 (1) 128 (1)

128 (2)128 (3)128 (4)

256 (1)

128 (3)128 (2)

128 (4)


to step 4

128 (1)128 (2)

128 (3)

PrxTarget


128 (1)

Step 5

128 (2)128 (1) 128 (1)

128 (2)128 (3)128 (4)

128 (1)128 (2)128 (3)128 (4)128 (5)


to step 4, noallocation to CR #5




Bit Rate Allocation – Increase Load




• Bitrate Upgrade





PrxNrtNew

Overload Control (TFCC)Example: UL

Reduce to nextlower bit rate

Estimate PrxTotalNew and

Lower bit ratesallowed

Switch bearerto CCH

More bearers

Decrease loading

Select randomly one of thehighest bit rate bearers

(A) PrxTotalNew > PrxTarget ANDPrxTotalChange < DeltaPrxMaxDown

(A)End

Yes

No

Yes

No

No

Yes

TFCC means TransportFormat Combination

Control Procedure, noDCH Downgrade but

suspend of highertransport formats


AC produces the TrCH parameters:

• Transport Formats (TF)

• Transport Format Combination (TFC)

• TFC identifiers

Overload Control (TFCC)

SupportedBitrates

0

TFCS (SL & RT RB)

TrCh 1

TFI0

TFI164

128

384

0

TFI2384

128

Peak BitrateIn Bearer

Parameters

SheduledBitrate

TFS for RT RBintermediate

Bitrates

64

128

0

TFS subsetFor TFCS

construction

64

0

TrCh 2

TFI0

TFI1

0

64

0

TFI1

TFI0TFI0

TFCC here


Example: DL Dedicated Channel Modification

BTS RNC-L2RNC-NBAP RNC-RRC RNC-RRM

BTS providesperiodical cell loadinformation to RRM

packet scheduling

PS indicates UE aboutthe modified capacityand selected UL TFC

subset

NBAP: RADIO RESOURCE INDICATION

UE

IubUu

RLC-PDU transportation on DCH

RR_ind

Capacity_modify

RLC-PDU transportation on modified DCH

UE in CELL_DCH state

[DCH] RRC: TRANSPORT FORMAT COMBINATION CONTROL

RRM detects overloadsituation in uplink


• In case of 3 bearers

• In case of 6 bearers

384

PrxTarget

Step 1 Step 2 Step 3

384

256

384

256

256

256

256

256

Step 1: 384 -> 256 (TFCC)Step 2: 384 -> 256 (TFCC)Allocation according to step 3

PrxTarget128

128

128


128

256

256

128

128

128

256

128

128

128

128

128

128

128

128

128

128128

128

128 Step 1: 256 -> 128 (TFCC)Step 2: 256 -> 128(TFCC)Step 3: 128 -> CCH (Radio Bearer Reconfiguration)Allocation according to step 4

Overload Control


• DeltaPrxMaxUp –WCELL (not implemented in RAN1.5.2 ED2)• Defines the maximum received uplink power increase in a cell, used when bit rates are allocated

or increased by the packet scheduler, relative to PrxTotal

• default value: 1.6dB; range: 0 ... 5 dB, step 0.2 dB

• DeltaPtxMaxUp-WCELL (not implemented in RAN1.5.2 ED2)• Defines the maximum transmitted downlink power increase in a cell, used when bit rates are

allocated or increased by the packet scheduler, relative to PtxTotal

• default value: 1.6dB; range: 0 ... 5 dB, step 0.2 dB

Bit Rate Allocation


• LoadControlPeriodPS• This parameter defines how often PS can perform load control actions for each bearer.

default value: 400ms; range: 100 ... 2000 ms, step 100 m

• Note: The value must not be smaller than scheduling period.

• DeltaPtxMaxDown(not implemented in RAN1.5.2 ED2)• Defines the maximum transmitted downlink power decrease in a cell, used when bit rates are

decreased by the packet scheduler, relative to PtxTotal.

• default value: 3dB; range: 0 ... 5 dB, step 0.2 dB

• DeltaPrxMaxDown (not implemented in RAN1.5.2 ED2)• Defines the maximum received uplink power decrease in a cell, used when bit rates are decreased

by the packet scheduler, relative to PrxTotal.

• default value: 3dB; range: 0 ... 5 dB, step 0.2 dB

Bit Rate Allocation



• Packet Transfer States & Parameters• Bitrate Allocation• Capacity Request & Traffic Volume Measurements • Channel Type Selection• Processing a Capacity Request• Packet Scheduler Interuption Timer

• Bitrate Upgrade





Dynamic Link Optimisation(DyLo) for NRT Traffic Coverage

BTS

UE384kbps

128kbps

Improved NRT traffic coverage

distanceRadio link is modified to use lower

bit rate when WBTS Tx power is getting close to maximum


Triggering of Dynamic Link Optimisation

time

Ptx, RLdistance

Ptx, ave

Triggering of DyLO

Ptx, maxOffset

Ptx, ave is averaged radio link power, measured and reported to RNC by BTSPtx, max is determined by admission control

The value of the Offset is fixed, 2 dB

Dynamic link optimisationis triggered if

Ptx, ave > Ptx, max - Offset


Decision algorithm

Triggering of DyLO

DyLO is not possible during compressed mode

DyLO is possible for NRT DCH allocations that have lasted at least 2 seconds (fixed guard time)

Not applicable in RAN1.5 (only 1 NRT DCH possible per UE)

• SF is doubled (physical channel bit rate reduced to half of the original)

• Additional puncturing is not allowed• DyLO cannot reduce bit rate below the Initial and

minimum allowed bit rate in downlink (RAN1.5.2ED CD19)

• DyLO can be started only if the current bit rate is higher than Maximum Allowed DL User Bitrate in HHO (enable compressed mode due to DL power)


Bit Rate Upgrade• After downgrade of DCH bit rate due to DyLO, upgrade of the bit rate

can be performed from the initial bit rate level only• Cell level parameter Initial and minimum allowed bit rate in

downlink is configurable by operator• Bit rate upgrade from any other bit rate is not possible• Bit rate upgrade is based on downlink traffic volume measurement

reports (capacity requests)• The change of the radio link power conditions does not trigger

upgrade• Possible triggering of the DyLO is checked before the bit rate is

upgraded, in order to avoid ping-pong effect (RAN1.5.2ED2)• New Ptx, max is calculated by AC according to the new bit rate• Initial Tx power Ptx, init is calculated by AC according to the new

bit rate• DyLO is possible if Ptx, init < (Ptx, max – Offset)• If inequality is not valid, the next lower bit rate is tried

Fixed, 2 dB


Related Parameters – operator controllable• WCEL: PtxDLAbsMax - Planned maximum downlink transmission power of a radio link

• The planned maximum downlink transmission power of radio link. This parameter is used in the downlink power allocation when CCTrCH includes one or more DCH's of interactive or background traffic class RAB's. The allocated power of a radio link cannot exceed the value of this parameter. The parameter is set separately for each cell. This parameter is the planned maximum, not the physical limit.Range and Step: -10...50 dBm, step 0.1 dBm, Default: 50 dBm

• WBTS: PtxDPCHmax - DPCH downlink transmission power maximum value• Parameter defines the maximum code channel output power for the power control dynamic range of BTS. The power

control dynamic range of BTS is the difference between the maximum and the minimum transmit output power of a code channel. The maximum transmission power is calculated by adding the value of the parameter to the BTS maximum output power (Pmax in dBm).Range and Step: -3...0 dB, step 0.1 dB, Default: –3 dBm

• WCEL: MinAllowedBitRateDL - Initial and minimum allowed bit rate in downlink• This parameter defines the minimum allowed bit rate in downlink that can be allocated by the PS. The allocated bit

rate corresponds to the highest bit rate in the TFS from which the TFCS is constructed.Range and Steps; 8, 16, 32, 64, 128, 256, 320, 384Default: 64 kbps (RAN1.5)

32 kbps (RAN04)

• WCEL: HHoMaxAllowedBitrateDL - Maximum Allowed DL User Bitrate in HHO• This parameter determines the bitrate threshold which the maximum allocated user bitrate on the downlink DPCH may

not exceed in order for the inter-frequency or inter-RAT (GSM) handover to be possible due to high downlink DPCH power level.Range and Steps: 32, 64, 128, 256, 384Default; 64 kbps (RAN1.5)

32 kbps (RAN04)


Related Parameters – fixed• Dynamic link optimisation usage

• Always used

• Downlink transmission power offset for dynamic link optimisation• 2 dB

• Guard time for dynamic link optimisation• 2 s


Restrictions• Radio link under DRNC

• Radio link under DRNC cannot trigger DyLO

• Compressed mode• DyLO is not allowed during the compressed mode measurements

• Dylo can be started only if the current bit rate is higher than Maximum Allowed DL User Bitrate in HHO (enable compressed mode due to DL power). Parameter minimum value is 32 kbps. So this parameter actually defines absolute minimum bitrate where DyLo can downgrade, even if the parameter MinAllowedBitRateDL has lower (8 or 16 kbps) value

=> if parameter HhoMaxAllowedBitrateDL > MinAllowedBitRateDL, DyLo never reach value set by parameter MinAllowedBitRateDL which it should reach before upgrade procedure can start =>upgrade is not happening

AAL2 resource modification is supported from RAN04 + CD2 on !


Bitrate Upgrade Possibilities in Nokia RAN

SF32(64k) SF8(384k) SF16(128k) CELL-FACH SF32(64k) SF8(384k) ○

Example: Max Bitrate 384kbps, Initial Bitrate 64kbps

Inactivity timers trigger release of resources

Bitrate[kbps]

time

RB setup32

64

128

384

Capacity Request DyLO triggered

Lightweight Flexible Upgrade feature active-Bitrate upgrade if sufficient resources available –

Maximum Bitrate > Allocated bitrate > InitialandMinAllowedBitrate

Capacity Request triggered from LFU feature

After RN2.0 CD3.0

Bitrate downgradeDue to DyLo


Example DyLO scheme 1: PtxDLabsMax 50 dBm, PtxTotalMax 43dBmDL

pw

r(dB

m)

PtxTotalMax 43dBm

PtxPrimaryCPICH 33dBm

PtxPrimaryCPICH – CPICHtoRefRABoffset = 31 dBm

PtxDLabsMax 50 dBm

Calculated max RL pwrCalculated max RL pwr - DLOptimisationPwrOffset

• This is where DyLO triggers. (If PtxDLabsMax is set high)

Default hidden value is 2dB

reftxP ,

max,txP

Ptx, threshold

(Existing WBTS Parameter PtxTotalMax (maximum total BTS power) is deleted)


Example DyLO scheme 2: PtxDLabsMax 38 dBm, PtxTotalMax 43dBmDL

pw

r(dB

m)

PtxTotalMax 43dBm

PtxPrimaryCPICH 33dBm

PtxPrimaryCPICH – CPICHtoRefRABoffset = 31 dBm

PtxDLabsMax 38 dBm

Calculated max RL pwr

PtxDLabsMax - DLOptimisationPwrOffset = 36 dBm

• PtxDLabsMax is reduced from 50dBm to 38dBm•This is where DyLO now triggers.

max,txP

reftxP ,

Ptx, threshold



• Packet Transfer States & Parameters• Bitrate Allocation• Capacity Request & Traffic Volume Measurements • Channel Type Selection• Processing a Capacity Request• Packet Scheduler Interuption Timer

• Bitrate Upgrade





Activation Time

• Activation time length is defined as a sum:

ActivationTime = ActivationTimeOffset + SignalingDelayOffset

• ActivationTimeOffset (Range: 0..2550 ms, step 10 ms) It represents the processing delay of RNC and BTS. It is function of timer_poll and includes RLC retransmissions

• The SignalingDelayOffset is RNC internal parameter that implies a required offset based on e.g. the SRB bit rate, the actual procedure and the lenght of a RRC message

• Call Setup time can be improved by tuning the parameter ActivationTimeOffset since it affects the behavior of Radio Bearer Setup and Radio Bearer Reconfiguration procedures


Activation Time improvement in RAN04

Service SRB3,4 SRB13,6

SDO in RAN04 CD2.1

AMR 320 80

CS 160 40

NRT PS 320 80

ATO recommended in RAN04 GCD3.0

All the services

700 700

20660NRT PS

ATO recommended in RAN04 GCD3.0

SRB13,6SRB3,4Service

300300All the services

0500CS

20660AMR

SDO in RAN04 GCD3.0

Activation time for AMR:SRB3.4: 320+700 = 1020 msSRB13.6: 80+700 = 780 ms

• In RAN04 the Activation Time is optimized from GCD3.0 on due to the shorter duration of the Activation Time Offset

Activation time for AMR:SRB3.4: 660+300 = 960 msSRB13.6: 20+300 = 320 ms

Call Setup delay

improved in 0.5 sec for SRB13.6!!

06 PacketScheduling 2006 Partner

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