Capacity Management

Outline

OverviewOverview

Capacity Management FunctionsCapacity Management Functions- Dedicated Monitored Resource HandlingDedicated Monitored Resource Handling- Admission ControlAdmission Control- Congestion ControlCongestion Control

Overview

Capacity Management is responsible for the control of the Capacity Management is responsible for the control of the load in the cell. It consists of 3 main functions:load in the cell. It consists of 3 main functions:

Dedicated Monitored Resource Handling:Dedicated Monitored Resource Handling: tracks utilization of tracks utilization of

critical resources of the system.critical resources of the system.

Admission Control:Admission Control: accepts/refuses admission requests based on the accepts/refuses admission requests based on the current load on the dedicated monitored resources and the characteristics of the current load on the dedicated monitored resources and the characteristics of the requestrequest

Congestion Control:Congestion Control: detects/resolves overload situationsdetects/resolves overload situations

Congestion Control Admission Control

Dedicated Monitored Resource Handling

Parameters

Capacity Management

OverviewCapacity Management Architecture Overview

Capacity Management functionality is located in the RNC. Capacity Management functionality is located in the RNC. The controlling RNC is responsible for the load and congestion control of its cells and the The controlling RNC is responsible for the load and congestion control of its cells and the execution of the admission control.execution of the admission control.

Dedicated Monitored Resources

The Dedicated Monitored Resources Handling function is The Dedicated Monitored Resources Handling function is responsible for collecting and providing information about the responsible for collecting and providing information about the utilization of resources that are critical to the load of the cell:utilization of resources that are critical to the load of the cell: by performing event-based and periodic measurementsby performing event-based and periodic measurements by keeping track of every link setup, addition, deletion and by keeping track of every link setup, addition, deletion and modification in the cell. modification in the cell.

Monitoring AlgorithmUpdate Cell Load Information→Downlink channelization codes MonitorDownlink channelization codes Monitor→Histogram MonitorHistogram Monitor→Downlink Transmitted Carrier PowerDownlink Transmitted Carrier Power→All interface Speech Equivalents (ASEs)All interface Speech Equivalents (ASEs)→Uplink Received Total Wideband Power (RTWP)Uplink Received Total Wideband Power (RTWP)→RBS hardware utilizationRBS hardware utilization

Measurements

Dedicated Monitored Resource Handling

Dedicated Monitored Resources

Resources monitored under the Capacity Management scope:Resources monitored under the Capacity Management scope:

Downlink Channelization Codes MonitorDownlink Channelization Codes Monitor: : provides a measure for code tree utilization in DL.provides a measure for code tree utilization in DL.

Histogram MonitorHistogram Monitor: : keeps track ofkeeps track of- SF usage in the DL: tracks the number of connections using a certain SF (except SF=16, reserved for HSDPA SF usage in the DL: tracks the number of connections using a certain SF (except SF=16, reserved for HSDPA

connections).connections).- SF usage in the ULSF usage in the UL- Number of Compressed Mode radio links: used to avoid too much interference from the compressed mode radio Number of Compressed Mode radio links: used to avoid too much interference from the compressed mode radio

users.users.- Number of users allocated to the HS-DSCHNumber of users allocated to the HS-DSCH

Downlink Transmitted Carrier Power MonitorDownlink Transmitted Carrier Power Monitor: : monitors the total amount of Non-HS downlink transmitted carrier power in the cell.monitors the total amount of Non-HS downlink transmitted carrier power in the cell.

All interface Speech Equivalent (ASE) MonitorAll interface Speech Equivalent (ASE) Monitor: : accounts for the air interface resources usage for DL and UL. The ASE of a radio link accounts for the air interface resources usage for DL and UL. The ASE of a radio link depends on the connection type and is expressed in terms of the equivalent number of speech radio bearers that generate the same amount of air depends on the connection type and is expressed in terms of the equivalent number of speech radio bearers that generate the same amount of air interface load.interface load.

Uplink received total wideband power (RTWP):Uplink received total wideband power (RTWP): provides information to Congestion Control regarding uplink interference.provides information to Congestion Control regarding uplink interference.

RBS Hardware Monitor: RBS Hardware Monitor: HW is a limited resource that depends on the amount of installed HW (channel elements) and the licensing restrictions.HW is a limited resource that depends on the amount of installed HW (channel elements) and the licensing restrictions.

Dedicated Monitored Resources

Admission Control Admission control accepts or refuses requests for utilization of dedicated Admission control accepts or refuses requests for utilization of dedicated

monitored resources. It is performed on cell basis.monitored resources. It is performed on cell basis.

The admission requests are initiated when:The admission requests are initiated when:- A new connection is set up. A new connection is set up. - An existing connection is modified.An existing connection is modified.- Soft Handover is performed.Soft Handover is performed.

The request for admission specifies the amount of resources that the radio connection requires:- Setup type: handover or new connection. Setup type: handover or new connection. - Service Class: guaranteed, guaranteed-hs or non-guaranteed service.Service Class: guaranteed, guaranteed-hs or non-guaranteed service.- Compressed mode resources requested if any.Compressed mode resources requested if any.- Downlink Transmitted Carrier Power requested if any.Downlink Transmitted Carrier Power requested if any.- Downlink Channelization Code resources requested if any.Downlink Channelization Code resources requested if any.- ASEs in uplink and downlink if any.ASEs in uplink and downlink if any.

The requirements are compared to the available resources and the configured The requirements are compared to the available resources and the configured limits for admission and the access is granted or denied.limits for admission and the access is granted or denied.

Admission ControlRAB request over the Iur interface

1. RAB request sent from SRNC to CRNC by means of RNSAP message over the Iur interface.

2. RNSAP is converted into RBs and DCHs attributes.

3. Required monitored resources are estimated on the basis of the set of DCHs and admission requested for those resources.

4. If request is admitted, the CRNC allocates necessary resources.

5. Admission Control informs SRNC by means of RNSAP message.

Admission Control

Non-guaranteed Non-guaranteed Traffic class ‘background ‘ or Traffic class ‘background ‘ or ‘interactive’ ‘interactive’

(Example: FTP and internet (Example: FTP and internet web services)web services)

GuaranteedGuaranteedTraffic class ‘conversational’ or Traffic class ‘conversational’ or ‘streaming’‘streaming’

(Example: speech and video (Example: speech and video services)services)

Guaranteed-hsGuaranteed-hs

HSDPA serviceHSDPA service

Non-Non-HandoverHandover

Best effort services. New Best effort services. New connections.connections.

New connectionsNew connections New connections.New connections.

HandoverHandover Best effort services. Add radio Best effort services. Add radio link for existing connections in link for existing connections in new cells.new cells.

Add radio link for existing Add radio link for existing connections in new cells.connections in new cells.

Add radio link for Add radio link for existing connection in existing connection in new cell.new cell.

Admission control is responsible forAdmission control is responsible for- Dividing the available resources among the non-guaranteed connections.Dividing the available resources among the non-guaranteed connections.- Differentiating access to guaranteed, guaranteed-hs and non-guaranteed Differentiating access to guaranteed, guaranteed-hs and non-guaranteed

connections.connections.- Reserving part of the dedicated monitored resources for handover Reserving part of the dedicated monitored resources for handover

connections.connections.

Combinations of requests for admission depending on setup type and service class

Non-guaranteed admission requests are blocked whenDL Code Usage > dlCodeAdm - beMarginDlCode

Guaranteed admission requests are blocked whenDL Code Usage > dlCodeAdm

Code blocking for non-handover requests is performed to reserve codes for users in handover.

Admission ControlThe Downlink Channelization Code Admission Policy

When a request is blocked on the downlink channelization code admission, the soft congestion mechanism is triggered.

No.DlCodeAdm

(%)beMarginDlCode

(%) Result1 2 0 RRC Connection Setup Rejected2 3 0 RRC Connection Setup Rejected

3 4 0 Voice call admitted, PS call rejected

4 35 0 Voice call admitted, PS call rejected

5 37 0SRB admitted, PDP context activation rejected.

6 39 0SRB admitted, PDP context activation rejected.

7 40 0 PS Call admitted up to 384 Kbps

Admission ControlTrial: Downlink Code Admission

Settings: beMarginDlCode=0 DlCodeAdmin=variable

Results:

Controls the SF usage in DL and UL at cell level, the number of radio links in compressed mode and the number of simultaneous HS-serving links in a cell.

Admission ControlThe Histogram Admission Policy

Requests demanding SF8 are blocked when usage of SF8 > sf8Adm

Requests demanding SF16 are blocked when usage of SF16 > sf16Adm

Requests demanding SF32 are blocked when usage of SF32 > sf32Adm

Non-guaranteed Service Class in DL

Admission Control

Guaranteed Service Class in DL

Requests demanding SF16 in DL (streaming PS16/128 radio connection type)are blocked when usage of SF16 > sf16gAdm

Guaranteed-hs Service Class in UL

Requests demanding SF4 in UL (PS384/HS radio connection type)are blocked when usage of SF4 > sf4AdmUl

By setting this parameter, the access for high and low consuming guaranteed services can be differentiated.

In cells where the optional PS384/HS radio connection is activated, this parameter may be reduced if the uplink experiences problems.

The Histogram Admission Policy (cont)

Admission Control

Compressed Mode Radio Links Limits

Requests demanding a radio link in compressed mode are blocked when Current number of radio links > compModeAdm

Number of Simultaneous HS-Serving Links Limits

The number of users allocated to the HS-DSCH may be limited to ensure sufficient end-to-end quality. Admission request will be blocked whennumber of users assigned to the HS-DSCH > hsdpaUsersAdm

The Histogram Admission Policy (cont)

The presence of connections using SF/2 compressed mode may degrade the quality of the common channels. That may be avoided by adjusting compModeAdm.

Admission ControlTrial: Histogram Admission

Settings: sf32Adm= 32 sf16Adm= 16 , 8 sf8Adm= 8 , 0

Results:

No. sf32Adm s16Adm sf8Adm Max Throughput (Kbps)1 32 16 8 3842 32 16 0 1283 32 0 0 64

Admission ControlThe Downlink Transmitted Carrier Power Admission Policy

Non-Guaranteed, Non-Handover requests are blocked when DTCP > pwrAdm - beMarginDlpwr

Guaranteed, Non-Handover & Non-Guaranteed, Handover requests are blocked whenDTCP > pwrAdm

Guaranteed, Handover & Guaranteed-hs requests are blocked whenDTCP > pwrAdm + pwrAdmOffset

This admission policy controls the downlink power utilized by R99 connections.

When a request is blocked on the DL Transmitted Carrier Power policy, the soft congestion mechanism is triggered.

No. pwrAdm (%)beMarginDlPwr

(%)pwrAdmOffset

(%)maxPwrMax

(dB) Result

1 13 0 0 4.8 RRC Connection Setup Rejected

2 16 0 0 4.8 RRC Connection Setup Rejected

3 17 0 0 4.8Signalling Radio Bearer admitted, but PDP context activation blocked

4 18 0 0 4.8 PS call admitted up to 64Kbps5 18 0 0 15 PS call admitted up to 384Kbps

Admission ControlTrial: Downlink Transmitted Carried Power Admission

Settings: beMarginDlPower=0 pwrAdmOffset=0 pwrAdm=variable maxpwerMax=15

Results:

Admission ControlThe ASE Admission PolicyProvides information of air interface usage per radio link type in cell for DL and UL.

The UL ASE Admission Policy

Non-Guaranteed, Non-Handover requests are blocked when ASE UL Usage > aseUlAdm - beMarginAseUl

Guaranteed, Non-Handover & Non-Guaranteed, Handover requests are blocked whenASE UL Usage > aseUlAdm

Guaranteed, Handover & Guaranteed-hs requests are blocked whenASE UL Usage > aseUlAdm + aseUlAdmOffset

ASE is the only resource for admission control on the UL

The DL ASE Admission Policy

Non-Guaranteed, Non-Handover requests are blocked when ASE DL Usage > aseDlAdm - beMarginAseDl

Non-Guaranteed, Handover & Guranteed & Guaranteed-hs requests are blocked whenASE DL Usage > aseDlAdm

Admission Control

Admission ControlTrial: ASE Admission

Settings: dlCodeAdm=100 beMarginDlCode=0 beMarginAseUl=0 aseUlAdm=500 beMarginDlPwr=0

Results:

No aseDlAdm Result1 1 CS Voice rejected, PS Rejected2 2 CS Voice rejected, PS Rejected3 3 CS Voice admitted, PS Rejected4 9 PS call admitted up to 64Kbps5 19 PS call admitted up to 128Kbps6 41 PS call admitted up to 384Kbps

Admission ControlThe RBS Hardware Admission Policy

Non-Guaranteed, Non-Handover requests are blocked when UL HW Usage > ulHwAdm - beMarginUlHw

Guaranteed, Non-Handover & Non-Guaranteed, Handover & Guaranteed-hs, Non-Handover requests are blocked whenUL HW Usage > ulHwAdm

Guaranteed, Handover & Guaranteed-hs,Handover requests are blocked when UL HW usage arrives at 100%

Provides information of hardware usage in a local cell group for DL and UL

The UL RBS Hardware Admission Policy

Admission Control

The DL RBS Hardware Admission Policy

Non-Guaranteed, Non-Handover requests are blocked when DL Hardware Usage > dlHwAdm - beMarginDlHw

Guaranteed, Non-Handover & Non-Guaranteed, Handover & Guaranteed-hs, Non-Handover requests are blocked whenDL Hardware Usage > dlHwAdm

Guaranteed, Handover & Guaranteed-hs,Handover requests are blocked when DL HW usage arrives at 100%

When a request is blocked on the DL RBS Admission, the soft congestion mechanism is triggered.

Admission ControlSoft Congestion Mechanism

The Soft Congestion Mechanism is triggered when a request for admission is blocked.

This mechanism consists of down-switching an non-guaranteed connection to a lower rate after ₋ a guaranteed admission control is blocked₋ a guaranteed-hs admission control is blocked ₋ a non-guaranteed admission control of a lower rate is blocked

The Soft Congestion mechanism targets connections originating over the Iu interface (present product not able to down-switch connections originating over the Iur interface)

Admission ControlSoft Congestion Mechanism (cont) Soft congestion triggered by non-guaranteed request blockingThe rate of an existing connection is reduced depending on the requested downlink rate:₋ request for 384 kbps blocked → not affect existing connections in cell₋ request for 128 kbps blocked → reduce exiting 384 kbps to 128 kbps₋ request for 64 kbps blocked reduce 384 kbps to 128 kbps or (if not 384 kbps connections available) reduce 128 kbps to 64 kpbs

Soft Congestion triggered by guaranteed request blockingThe non-guaranteed connections are targeted in decreasing order of their downlink rate (first 384 kbps connections are reduced, then 128 kbps connections are targeted, …)

Congestion ControlCongestion Control Detection

Congestion is detected in the RNC by means of measurements of the Downlink Transmitted Carrier Power and the Uplink Received Total Wideband Power.

The Downlink Transmitted Carrier Power is continuously measured. When the power goes above a predefined threshold, an event–based measurement is sent to the RNC. As long as the power is above the threshold, an event – based report is sent to the RNC every second.

DL Cell Congestion Detection

Congestion Control

DL congestion is solved when the DTCP is below the setup threshold for longer that the hysteresis time or until next periodic event-based measurement indicating DTCP below threshold arrives.

Congestion ControlUL Cell Congestion Detection

UL congestion is solved when the Uplink RTWP is below the setup threshold for longer that the hysteresis time or until next periodic event-based measurement indicating URTWP below threshold arrives.

Congestion ControlCongestion Resolve Handling

Congestion Control

Non-guaranteed connections are targeted immediately: their Non-guaranteed connections are targeted immediately: their rate is decreased rate is decreased

If congestion persists and there are no more Non-guaranteed If congestion persists and there are no more Non-guaranteed connections, the resolve actions start for Guaranteed-hs connections, the resolve actions start for Guaranteed-hs connections. They will be dropped. connections. They will be dropped.

The guaranteed services are the last ones to be targeted by The guaranteed services are the last ones to be targeted by Congestion control. The resolve actions on Guaranteed services Congestion control. The resolve actions on Guaranteed services are more severe, causing the drop of the connections.are more severe, causing the drop of the connections.

Congestion resolve actions in mixed services congested cell:

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