3g load control

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HUAWEI TECHNOLOGIES CO., LTD.

3G Load Control

February 2012


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HISILICON SEMICONDUCTOR

HUAWEI TECHNOLOGIES CO., LTD. Page 2 Page 2

Contents

Load Control: Introduction

Load Control: Intelligent Access Control

Load Control: Load Reshuffling


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Load Control exists in all phases

Load Control is used to keep system stable, maximize system capacity while ensuring the cover

3. After UE access2. During UE access1. Before UE access

Time

LDRCACPUC

OLC

IAC

PUC: Potential User Control

CAC: Call Admission Control

IAC: Intelligent Admission Control

LDR: Load Reshuffling

OLC: Overload Control


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Load control features

PUC

The function of PUC is to balance traffic load among inter-frequency cells. By modifying cell sel

reselection parameters and broadcasting them through system information, PUC leads UEs to c

The UEs may be in idle mode, CELL_FACH state, CELL_PCH state, or URA_PCH state.

CAC

The function of CAC is to decide on resource requests from UEs, such as access, reconfigurati

requests or service request, according to the resource status of the cell (codes, power, credits,

IAC

The function of IAC is to increase the access success rate with the current QoS assured throug

queuing, preemption, and Direct Retry Decision (DRD).


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LDR

The function of LDR is to reduce the load of a cell when the available resources of the cell reac

threshold. The purpose of LDR is to increase the access success rate in the following ways:

Inter-frequency load handover

Code reshuffling

BE service rate reduction

AMR voice service rate reduction

Uncontrolled realtime traffic QoS renegotiation

CS inter-RAT load handover

PS inter-RAT load handover

OLC

The function of OLC is to reduce the cell load rapidly by restricting the Transport Format (TF) o

releasing UEs when the cell is overloaded. The purpose of OLC is to ensure the stability of the

of most UEs.


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LDR

The function of LDR is to reduce the load of a cell when the available resources of the cell reac

threshold. The purpose of LDR is to increase the access success rate in the following ways:

Inter-frequency load handover

Code reshuffling

BE service rate reduction

AMR voice service rate reduction

Uncontrolled realtime traffic QoS renegotiation

CS inter-RAT load handover

PS inter-RAT load handover

OLC

The function of OLC is to reduce the cell load rapidly by restricting the Transport Format (TF) o

releasing UEs when the cell is overloaded. The purpose of OLC is to ensure the stability of the

of most UEs.

How to check

LST UCELLALG


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Contents





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Load Control: IAC

Intelligent Access Control (IAC) function target is to increase RRC and RAB success rate and it is d

parts.

IAC for RRC

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RRCconnection

request

Service-basedredirection

Redirection

RRC CAC

DRD

SUCCEED


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Load Control: IAC (RRC)

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Service-based

redirection

Depending on requested service and cell load, appropriate cell is chosen. For example, PS calls casecond carrier or voice calls can be redirected to interRAT neighbors.

RRC CONNECTION REJECT (Redirection info) is sent to UE with cell reselection for Inter-freq acc

access.

Redirection

RRCconnection

request


Redirection

RRC CAC


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Page 10

Service-based

redirection

Depending on requested service and cell load, appropriate cell is chosen. For example, PS calls casecond carrier or voice calls can be redirected to interRAT neighbors.

RRC CONNECTION REJECT (Redirection info) is sent to UE with cell reselection for Inter-freq acc

access.

RedirectionHow to check redirection:

LST UREDIRECTION

RRCconnection

request


Redirection

RRC CAC


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Page 11

RRC CAC

Code

RRC connection request and HO services only need to have available codes Other services needs to leave at least DLHoCeCodeResvSF

Power In case cell load is higher than UL or DL OLC trigger, RRC requests are not accepted.

Credits

RRC connection request and HO services only need to have available credits

Other services needs to leave at least DLHoCeCodeResvS

Iub Check if there is available bandwidth for this signalling connection

RRCconnection

request


Redirection

RRC CAC


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RRC CAC

Code

RRC connection request and HO services only need to have available codes Other services needs to leave at least DLHoCeCodeResvSF

Power In case cell load is higher than UL or DL OLC trigger, RRC requests are not accepted.

Credits

RRC connection request and HO services only need to have available credits

Other services needs to leave at least DLHoCeCodeResvS

Iub Check if there is available bandwidth for this signalling connection

How to LST UCE

How to

LST UCE

RRCconnection

request


Redirection

RRC CAC


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Page 13

DRD

After admission fail, DRD tries to select another cell among cells with same coverage (blind HO). Insuccess to access, another one in the list is tried.

In case there is no more appropriate neighbors, redirection is done (in case switch is ON)

RRCconnection

request


Redirection

RRC CAC


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Page 14

DRD

After admission fail, DRD tries to select another cell among cells with same coverage (blind HO). Insuccess to access, another one in the list is tried.

In case there is no more appropriate neighbors, redirection is done (in case switch is ON).

RRCconnection

request


Redirection

RRC CAC

How to check redirection status:

LST UDRD


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Load Control: IAC (RAB)

IAC for RAB

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RAB setuprequest

Inter-freqDRD

Ratenegotiation

Try anotherneighbor cell

Fa

SUCC

CAC SUCC


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Target is to select a suitable cell for UE to access according to service priority and cell load (in caseactive). RNC prepares a list with blind HO neighbors and assigns cell with highest service priori

MBR, GBR, initial bit rate and target bit rate are assigned.

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Inter-freqDRD

Ratenegotiation

RAB setuprequest

Inter-freqDRD

Ratenegotiation


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Target is to select a suitable cell for UE to access according to service priority and cell load (in caseactive). RNC prepares a list with blind HO neighbors and assigns cell with highest service priori

MBR, GBR, initial bit rate and target bit rate are assigned.

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Inter-freqDRD

Ratenegotiation

How to check inter-freq DRD status:

LST UDRD

RAB setuprequest

Inter-freqDRD

Ratenegotiation


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RAB CAC

Code Need to leave at least DLHoCeCodeResvSF

Power

Three different algorithms. Firstly UL is checked, then DL.

UL uses Algorithm 2: ENU

DL uses Algorithm 1: Load increase

Credits Need to leave at least DLHoCeCodeResvS

Iub Check if there is available bandwidth for GBR

User Max

Max cell HSDPA /HSUPA user number and max NodeB HSDPA/HSUPA user number is taking intonumber exceeds, user is degraded to R99.

RAB setuprequest

Inter-freqDRD

Ratenegotiation


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RAB CAC

Code Need to leave at least DLHoCeCodeResvSF

Power

Three different algorithms. Firstly UL is checked, then DL.

UL uses Algorithm 2: ENU

DL uses Algorithm 1: Load increase

Credits Need to leave at least DLHoCeCodeResvS

Iub Check if there is available bandwidth for GBR

User Max

Max cell HSDPA /HSUPA user number and max NodeB HSDPA/HSUPA user number is taking intonumber exceeds, user is degraded to R99.

How to check if User Max is enabled (HSxPA_UU_ADCTRL switch):

LST UCELLALGOSWITCH

How to check algorithm:

LST UCELLALGOSWITCH

How to CAC thresholds:

LST UCELLCAC

RAB setuprequest

Inter-freqDRD

Ratenegotiation


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In case admission fails, another neighbor cell is tried from the suitable list. Then Rate Negotiation aIn case all neighbors fails:

If requested service is HSDPA, services is degraded to R99 to try again.

If requested service is R99, interRAT DRD is tried (needs bling HO 3G2G neighbors)

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RAB setuprequest

Inter-freqDRD

Ratenegotiation

Try anotherneighbor

cell


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Contents





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Load Control: LDR

The function of LDR is to reduce the load of a cell when the available resources of the cell reach th

congestion threshold.

Basic congestion state can be caused by insufficiency of power, codes, Iub or credits resources.

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Load Control: LDR

The function of LDR is to reduce the load of a cell when the available resources of the cell reach th

congestion threshold.

Basic congestion state can be caused by insufficiency of power, codes, Iub or credits resources.

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How toLST UCE

LST UN

LST UCE


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Load Control: LDR

When the cell is in basic congestion, RNC can take one of follow actions each period (duration set

ULDCPERIOD):

The list of actions and its order could be modified using MOD UCELLLDR.

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Resource UL/DL

LDR Actions

Inter-Freq HO

BE RateReduction

Inter-

RAT

CS HO

Inter-

RAT PS

HO

AMRReduction

Iu QoSRenegotiation

CodeReshuffling

MBMS PowerDowngrading

Power

Resource

UL

DL

Code

Resource

UL .

DL

NodeB Credit

UL

DL

Iub TransportResource

UL DL


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