Different Dual Band Strategy Analysis

8/3/2019 Different Dual Band Strategy Analysis

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HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

Huawei Confidential

Security Level:2012/4/22

Different Dual BandStrategy Analysis


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HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 2

Dual Band is introduced in order to increase the capacity of the network. Due

to the propagation feature of frequency of 900M and 1800M, the path loss is

different between 900M and 1800M around 7dB.

Because of the path loss differences, the MS usually select and reselect the

900M cells. During the handovers (mostly PBGT HO), the MS most likely will

choose 900M cells also. How to balance the traffic becomes our main topic.

In order to balance the traffic, We can tune layer, cell selection, cell

reselection and handover parameters. Also TRX transmit power of 900M and

1800M can be fine tuned.

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I. CO-BCCH

II. Dual Band + 1800M Bared + Same Layer

III. Dual Band + Not Bared + Different Layer

IV. Dual Band + Not Bared + Same Layer

V. Enhanced Dual Band + Not Bared + Same Layer

VI. Metrics of Evaluation and Suitable Scenario

VII. How to Balance the Traffic

VIII. Conclusion

Page 3


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CO-BCCHAdvantage:

Increase the capacity

The traffic will be easy to balance

Simple the network structure (NL, LAC and CI)

Disadvantage:

HO times can be increased

HSR will decrease due to blind U-O HO

If 900M is down, whole cell is down

Can not catch 1800M roamers

PBGT HO request will decrease

Will be hard to distinguish between the hardware

problem and configuration problem

Handover from 900M to 1800M is blind HO

Suitable Scenario:

Overlaid Continuous coverage

If 1800M does not have continuous coverage ,900M

TRX number >= 1800M TRX number in order to avoid

congestion

Cell Radius < 800m

Users are not far from the site

GSM900 subcell

DCS1800 subcell

BCCH/SDCCH/TCH/PDTCH

TCH

Assignment U-O handover


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HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

The main parameters of CO-BCCH

Page 5

Application scenario typeLayer of

the Cell

EnhancedConcentric

Allowed

RXLEV_AC

CESS_MIN

Cell_Bar_A

ccessCRO(2dB) ECSC MBR

Load HO

Allowed

ConcentricCircles HO

Allowed

COBCCH/concentric cell 3 YES 3 No 0 YES 0 YES YES

Application scenario type

Edge HO

DL RX_LEVThreshold

UL to OL

HOAllowed

OL to UL

HOAllowed

RX_LEV for

UO HOAllowed

RX_QUAL

for UO HOAllowed

TA for UO

HOAllowed

Assign

OptimumLayer

Assign-

optimum-level

Threshold

Pref.

Subcell inHO of

Intra-BSC

COBCCH/concentric cell 20 YES YES YES NO No

System

Optimizatio

n

30

System

Optimizatio

n


Incoming-

to-BSC HO

Optimum

Layer

EnhancedConcentric

Allowed

UtoOTraffic HO

Allowed

Cell TypeInter-layer

HO

Threshold

Inter-layerHO

Hysteresis

Busy

Threshold

of TCH

Traffic in

Overlaid

Subcell

Tch Traffic

Busy

Underlay

Threshold

MS_TXPWR_MAX_CC

H

COBCCH/concentric cellUnderlaid

SubcellYes NO

Concentric

cell/ / 70 60 5


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Dual Band + 1800M Bared + Same Layer

Advantage:

PBGT HO times will go up

Disadvantage:

1800M can be access only from HO

Number of HO can be increased (if there is

UL/DL quality of 1800M, or RF problem of 1800M,

Ping-Pong HO will happen)

Traffic not balance, 900M has more traffic

Can not catch 1800M roamers

Will be hard to distinguish between the

hardware problem and configuration problem

Suitable Scenario:

Users are not far from the site

Not in the 1800M roaming area

GSM900 subcell

DCS1800 subcell

BCCH/SDCCH/TCH/

PDTCH


Access

PBGT handoverEmergency handover

and etc.


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Application scenario type Layer of the CellRXLEV_ACCESS_

MINCell_Bar_Access ECSC MBR

DualBand 1800M Bared Same Layer(900M) 3 3 No YES 2

DualBand 1800M Bared Same Layer(1800M) 3 3 Yes YES 2

Application scenario type Load HO AllowedMS_TXPWR_MA

X_CCH

PBGT HO

Threshold

LOAD

HANDOVER

THRESHOLD(%)

LOAD REQ. ON

CANDIDATE

CELL(%)

DualBand 1800M Bared Same Layer(900M) YES 5 50ACCORDINGTHE TRAFFIC

ACCORDINGTHE TRAFFIC

DualBand 1800M Bared Same Layer(1800M) YES 0 127ACCORDING

THE TRAFFIC

ACCORDING

THE TRAFFIC

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The parameters(Dual Band + 1800M Bared + Same Layer)


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Dual Band + Not Bared + Different Layer

Advantage:

Easy to Catch 1800M roamers

Traffic is well balance by optimizing Idle Mode

Parameters and HO Parameters

Good for continuous coverage of 1800M /900M in

huge network

Disadvantage:

PBGT HO request will shift to the other type of HO

Network structure will be complicated (NL)

Suitable Scenario:

Continuous coverage of 1800M

Micro cells

Roaming Area

Selection and Reselection

GSM900 subcell

DCS1800 subcell


Layer HO threshold

900M PBGT HO threshold


Inter-Layer handoverand etc.

Emergency handoverand etc.


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The parameters(Dual Band + Not Bared + Different Layer)

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Application scenario typeLayer of the

Cell

Enhanced

Concentric

Allowed

RXLEV_ACCESS

_MIN

Cell_Bar_Acces

sCRO(2dB) ECSC MBR

Dual Band Not Bared Same Layer(900M) 3 NO 3 NO 0 YES 2

Dual Band Not Bared Same Layer(1800M) 2 NO 3 NO 6-10 YES 2

Application scenario typeLevel HO

Allowed

Concentric

Circles HO

Allowed

Edge HO DL

RX_LEV

Threshold

PBGT HO

Allowed

MS_TXPWR_M

AX_CCH

LOAD

HANDOVER

THRESHOLD(%)

LOAD REQ. ON

CANDIDATE

CELL(%)

Dual Band Not Bared Same Layer(900M) NO NO 20 YES 5

ACCORDING

THE

TRAFFIC

ACCORDING

THE

TRAFFIC

Dual Band Not Bared Same Layer(1800M) NO NO 20 YES 0

ACCORDING

THE

TRAFFIC

ACCORDING

THE

TRAFFIC


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Dual Band + Not Bared + Same Layer

Advantage:

Easy to Catch 1800M roamers

PBGT HO will increase

No need continuous coverage

Disadvantage:

Neighbor Cells relations will be complicated

Need time to optimized the parameters

It is not easy to balance the traffic

Suitable Scenario:

The beginning of the network, 900M&1800M

without continuous coverage

1800M with more power

Selection and Reselection

GSM900 subcell

DCS1800 subcell





PBGT handoverand etc.



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The parameters(Dual Band + Not Bared + Same Layer)


Layer of the

Cell

RXLEV_ACC

ESS_MIN

Cell_Bar_Ac

cess CRO(2dB) ECSC MBR

Load HO

Allowed

Dual Band Not Bared Different Layer(900M) 3 3 NO 0 YES 2 YES

Dual Band Not Bared Different Layer(1800M) 3 3 NO 6-10 YES 2 YES

Application scenario type MBRLoad HO

Allowed

LOAD

HANDOVER

THRESHOLD

(%)

LOAD REQ.

ON

CANDIDATE

CELL(%)

Level HO

Allowed

Edge HO DL

RX_LEV

Threshold

MS_TXPWR

_MAX_CCH

Dual Band Not Bared Different Layer(900M) 2 YES

ACCORDIN

G THETRAFFIC

ACCORDIN

G THETRAFFIC

YES 18 5

Dual Band Not Bared Different Layer(1800M) 2 YES

ACCORDIN

G THE

TRAFFIC

ACCORDIN

G THE

TRAFFIC

YES 16 0

Page 11


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Enhance Dual Band + Nor Bared + Same Layer

Advantage:

The traffic will be balanced

PBGT HO will increase

Disadvantage:

Just suitable for 900M/1800M have the same coverage

Neighbor Cells relations will be complicated

Suitable Scenario:

1800M coverage is not continuous

Under Laid has almost the same coverage with

Overlaid

GSM900 subcell

DCS1800 subcell


Assignment U-O handover

PBGT HO



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The parameters(Enhance Dual Band + Not Bared + Same Layer)


Layer of the

Cell

RXLEV_ACC

ESS_MIN

Cell_Bar_Ac

cess CRO(2dB) ECSC MBR

Load HO

Allowed

Dual Band Not Bared Different Layer(900M) 3 3 NO 0 YES 2 YES

Dual Band Not Bared Different Layer(1800M) 3 3 NO 6-10 YES 2 YES


LOAD

HANDOVER

THRESHOLD

(%)

LOAD REQ.

ON

CANDIDATE

CELL(%)

MS_TXPWR

_MAX_CCH

Assign

Optimum

Layer

Concentric

Circles HO

Allowed

Assign-

optimum-

level

Threshold

Enhanced

Concentric

Allowed

Dual Band Not Bared Different Layer(900M)

ACCORDIN

G THETRAFFIC

ACCORDIN

G THETRAFFIC

5

System

Optimization

Yes 35 Yes

Dual Band Not Bared Different Layer(1800M)

ACCORDIN

G THE

TRAFFIC

ACCORDIN

G THE

TRAFFIC

0

System

Optimizatio

n

Yes 35 Yes

Page 13


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Matrix of Evaluation and

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Evaluation of Different Dual Band Type

Suitable Scenario of Different Dual Band Type

CO-BCCHDual Band + 1800M

Bared + Same Layer

Dual Band + Not Bared +

Different Layer

Dual Band + Not Bared +

Same Layer

Enhanced Dual band + Not

Bared + Same Layer

Suitable for Roaming Area No No Yes Yes Yes

Suitable for 1800M ContinuousCoverage

Yes No Yes Yes No

Suitable for User Near the site Yes Yes Yes Yes Yes

Suitable for Micro Site / No Yes Yes /

Traffic Balace Easy Middle Easy Difficult Very Easy

Special Requirement No No NoAlmost the Same Coverage

of 900M/1800M

Almost the Same Coverage

of 900M/1801M

CO-BCCH Dual Band + 1800MBared + Same Layer Dual Band + Not Bared +Different Layer Dual Band + Not Bared +Same Layer Enhanced Dual band + NotBared + Same Layer

Traffic Balance 4 2 5 0 5

Catch 1800M Roamer 0 0 5 5 5

Increase Capacity 5 3 3 3 4

Simple the Network Structure 5 0 0 0 0

Mobility Performance 3 3 5 5 5

RF or Hardware problem

impaction 0 0 3 3 2


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How to Balance the Traffic

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Function of 900M and 1800M in dual band

Layer 4

Layer 3

Layer 2

Layer 1

GSM Umbrella 900

GSM Macro 900 GSM Macro 900

GSM Micro 900

GSM Macro1800 GSM Macro 1800

GSM Micro 1800 GSM Micro 900 GSM Micro 1800

900M mostly used in high layer for mobility and1800M mostly used in low layer for capacity,

normally, we should configure more TRX number in 1800M cells than in 900M cells.

Usually 1800M should take high ratio of traffic than 900M, and normally we should keep 900M a

little free to promise the coverage and mobility.


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Page 16

Traffic Balance Control Flow

Selection Reselection

GSM900 subcell

DCS1800 subcell

GSM900 subcell

DCS1800 subcell

GSM900 subcell

DCS1800 subcell

Assignment

GSM900 subcell

DCS1800 subcell

Handover

C1=RxLev - Rxlev_Access_Min

C2=C1 + CRO

PIPT

TO

Assign Optimum LayerAssign-optimum-levelThresholdTA Threshold ofAssignment Pref.

1. Load HO Allowed2. Level HO Allowed3. Concentric Allowed4. Enhanced Concentric

Allowed5. PBGT HO6. Fast Move HO

7. Edge HO8. Emergency HO

ALL Dual Band Type ALL Dual Band Type CO-BCCHEnhance Dual Band

CO-BCCH (1,3,4,5,7,8)Dual band+ Same Layer(1,5,7,8)Dual band + Different Layer(1,2,6,7,8)Enhance Dual Band(1,3,4,5,7,8)


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Traffic Balance Control Flow Step1: Cell Selection

GSM900 subcell

DCS1800 subcell

C1 = RxLev RxLev _ Access _ Min

The MS will choose the Cell with the biggest C1 to stay when it power on

GSM900 subcell

DCS1800 subcell

TRX Transmit Power Cell Parameter

GSM900 subcell

DCS1800 subcell

GSM900 subcell

DCS1800 subcell

-80 dbm

-90 dbm

-90 dbm

-80 dbm

If Rxlev_Access_Min thesame with each other

Selection Selection

Rxlev C1

Rxlev_Access_Min C1

Normally, we configure 1800M with

low Rxlev_Access_Min in dual band,

to make 1800M cells easy to be

selected.


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Page 18

Traffic Balance Control Flow Step2: Cell Reselection

GSM900 subcell

DCS1800 subcell

C2= C1 + CRO (PT 31)

The MS will choose the Cell with the biggest C2 to stay during cell reselection

GSM900 subcell

DCS1800 subcell

RxLev RxLev _ Access _ Min Cell Parameter

GSM900 subcell

DCS1800 subcell

GSM900 subcell

DCS1800 subcell

Rxlev C2

Rxlev_Access_Min C2

CRO C2

C1=30CRO=0

C1=25CRO=0

C1=28

CRO=6

C1=25

CRO=6

C2=30C2=25

C2=40

C2=37

Resection

Normally, we configure 1800M with

high CRO in dual band, to make 1800M

cells easy to be selected.


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Page 19

Traffic Balance Control Flow Step3: Assignment

Assignment in dual band just happen in CO-BCCH and Enhance Dual Band

Assign Optimum Layer

Assign-optimum-level Threshold

TA Threshold of Assignment Pref. GSM900 subcell

DCS1800 subcell

GSM900 subcell

DCS1800 subcell

Request Assignment

GSM900 subcell

DCS1800 subcell

GSM900 subcell

DCS1800 subcell

Request Assignment

TA

RxLev

TCH assignment will check Assign-

optimum-level Threshold and TA

Threshold of Assignment Pref.When Assign Optimum Layer =

System Optimization, Rxlev >= Assign-

optimum-level Threshold and TA


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Page 20

Traffic Balance Control Flow Step4: Handover

With the same layer, to change PBGT Threshold to push traffic to 1800M

With different layer, to change Inter-layer HO Threshold to push traffic to 1800M

GSM900 subcell

DCS1800 subcell

Same Layer

For 1800M outgoing cell HO, to configure high PBGT

HO Threshold to make PBGT HO hard to occur;

For 1800M incoming cell HO, to configure high PBGTHO Threshold to make PBGT HO easy to occur;

Outgoing Cell HO Incoming Cell HO

900M Cell 50 127

1800M Cell 127 50

Easy DifficultPBGT HO

GSM900 subcell

DCS1800 subcell

Layer HO threshold


Inter-Layer handoverand etc.


Different Layer

Use level HO, it easy to keep user in 1800M layer

by adjust Inter-layer HO Threshold

When Rxlev > Inter-layer HO Threshold and

content P/N rule, the user will HO to 1800M and

keep there until other type of HO occur;


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HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 21Page 21

Before we add 1800M, we need to check the traffic area, if the traffic is far

from the cell, there will be no traffic balance. So the best way is to put the

Micro site in that hot point.

The best suitable solution for the network is Dual Band + Not Bared +

Different Layer:

Traffic will be balanced

Suitable for the network growth

Suitable for Micro cell

It easy to distinguish hardware problem or parameters problem if traffic is not balance


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Documents

Different Dual Band Strategy Analysis