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HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

www.huawei.com

Huawei Dualband Co-BCCH

Cell Introduction

Huawei RNP & RNO

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Basis

Why

How

3.

1.

2. What

4.

5. Risk

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Basis

Distance from

cell antenna

S

ignalStrength

(dBm)

-95

-75

0.5 km 1 km

GSM900

DCS1800

MS REPORTED RXLEV

GSM900

GSM1800

MS Can't Measure RXLEV

Different path loss

Co-BCCH Introduct ion

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What

Concentric Cell

Enhanced Concentric Cell

Co-BCCH Cell

Common BCCH Cell , also cal led GSM900&DCS1800, Mult i -band cel l ;

Based on Enhanced Concentr ic Cell Algo r i thm;

UL provid es BCCH, SDCCH,PDCH and TCH channels,

wh i le OL on ly prov ides the TCH channels

UL(GSM 900) carries BCCH, SDCCH, PDCH & TCH, For Coverage

OL(DCS 1800) contains only TCH, For Traffic Load

Co-BCCH Introduct ion

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Why

Frequency restrict:

The frequency resource doesnt support high configuration

Improve capability:

UL and OL share the BCCH, SDCCH, PDCH, and the TCH

channels will be increased accordingly Simplify network structure:

Reduce number of cells in the network

Reduce number of neighboring cells

Simplify multi-layer network into one layer network

Co-BCCH Introduct ion

GSM900 BCCH

SDCCH/TCH

DCS1800 TCH

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How

TCH Assignment procedure

Handover procedure

Base on: RxlevRxqualTA

Specially: Classmark 3 which has higher priority than TA\Lev\Qual

If did not know classmark 3, only assign the BCCH GSM900 BCCH

SDCCH/TCH

DCS1800 TCH

Co-BCCH Introuct ion

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5 steps

CellType Co-CellProperty

Avoid blind assignment failurearose by single band MSSet Enhanced

Co-cell Allowed

Be adjacent to itself

automatically

Enable BSC

getting MRs of UL

when MS is

occupying TCH

on OL.

Cell Parameter Sett ing

Activate Co-BCCH Cell

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Assign Optimum Layer

System optimization is recommended in Co-BCCH Cell, which indicates thesystem selects the optimum layer for TCH assignment as according to uplink

signal strength in MRs provided through the UL's SDCCH

Assign-Optimum-Level Thrsh.

Range: 0~63, (-110dBm~-47dBm). 28-35 is recommended

TA Thrsh. of Assignment Pref. Range: 0~255. 63 is recommended

UL Rx-Lev > Assign-Optimum-Level Thrsh. &

TA < TA Thrsh. Of Assignment Pref.

UL Re-Lev < Assign-Optimum-Level Thrsh. Or

TA > TA Thrsh. Of Assignment Pref.

OL ULSystem

optimization

Mode

Cell Parameter Sett ing

Assignment

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Handover

Parameters Value

UL to OL HO Allowed Yes

OL to UL HO Allowed Yes

Rx_Lev for Concentric Cell HO Allowed Yes

OL to UL HO received level Thrsh. 20

UL to OL HO received level Thrsh. 30

Rx_Qual for Concentric Cell HO Allowed No

Receiving Quality Thrsh. 60

TA Concentric Cell HO Allowed No

TA Thrsh. 63

TA hysteresis 0

UL to OL Traffic HO Allowed No

Traffic Thrsh. of underlaid 70

Underlaid HO Step period 5

Underlaid HO Step level 5

OL subcell UL subcell

DL Rx-Lev >= U to O HO received level Thrsh.&

DL RxQual < Receiving Quality Thrsh. &

TA < (TA Thrsh. - TA Hysteresis) &

Traffic in Underlay > Traffic Thrsh. of underlay

DL Rx-Lev < O to U HO received level Thrsh. or

DL Rx-Qual >= Receiving Quality Thrsh. or

TA > (TA Thrsh. + TA Hysteresis)

Cell Parameter Sett ing

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Pref. subcell in HO of intra-BSC

Range: System Optimization, OL, UL

Recommended: UL. UL is preferred during the intra-BSC HO.

Incoming-to-BSC HO optimum layer

Range: UL, OL

Recommended: UL. UL is preferred during the incoming-to-BSC HO.

ULOL

UL configured for incoming

handover

Setp1: Handover into UL is

preferred

Setp2: If UL is busy enough, handover

into OL is performed

Setp3:DLRx-Lev of OL is weak,

return to source cell

Cell Parameter Sett ing

Handover

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Properly setting OL to UL HO received level Thrshand UL to OL HO received

level Thrsh.

Penalty Time of UL to OL HO (s): When handed over from UL to OL, If "Penalty

allowed" set to "Yes", system will forbidden MS to handover back to the UL during

the "Penalty Time of UL to OL HO (S)". Range:0~255(s)

Disable intra-cell handover

OL

ULUL to OL HO received level Thrsh.

OL to UL HO received level Thrsh.

Hysteresis1800M users

900M & 1800M users

900M users RX_LEV_ACCESS_MIN

Hysteresis (typical value is 8-12dB) =

UL to OL received level Thrsh. -OL toUL received level Thrsh.

The higher the hysteresis, the fewer the

ping-pong HO between UL and OL, also

traffic distribution will be changed.

Cell Parameter Sett ing

Protection against Ping Pong HO

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Summary

Parameters for Assignment Control

ParametersRecommended

ValueDetails

Assign optimum

layer

System

optimization

1.system optimization: traffic distribution can be changed to adapt real traffic

model by tuning Assign-Optimum-Level Thrsh, which can preventing

congestion on UL, while make good use of OL.

2.UL: calls will be assigned to UL.3.OL: calls will assigned out of OL coverage

Assign-Optimum-

Level Thrsh.23-28

1.Valid if Assign optimum layer is setSystem optimization.

2.The lower the parameter, the more calls assigned in OL. However, TCH

Assignment success rate may decrease.

TA Thrsh. ofAssignment Pref.

63 Valid if Assign optimum layer is setSystem optimization.

Optimization for Assignment

Traffic Optimization Strategy

Optimization ResultsUL OL

Assign optimum

layer

Assign-Optimum-

Level Thrsh.

congested idle System optimization Congestion HSR Ass-Succ may

normalSlightly

congestedSystem optimization Congestion HSR Ass-Succ

idle congested Underlaid subcell Congestion HSR Ass-Succ

Cell Parameter Sett ing

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Parameters for Handover Control

ParametersRecommended

ValueDetails

Pref. subcell in HO of intra-BSCsystem

optimization

UL: keep good handover performance

system optimization: balance UL and OL traffic

Incoming-to-BSC HO optimum layer ULUL: keep good handover performance

OL: maybe out of OL coverage, risk exists.

Rx_Lev for Concentric Cell HO Allowed YesDetermine whether the receiving level or quality of

downlink, or TA is taken as the judgment condition in

the Concentric Cell handover judgment. Rx_Lev isabsolutely necessarily. Quality and TA is optional.

Rx_Qual for Concentric Cell HO Allowed Yes

TA Concentric Cell HO Allowed No

UL to OL Traffic HO Allowed NoDetermines whether the traffic in UL is one of conditions

for OL to overlaid handover.

Optimization for handover

Issues of Co-BCCH CellPref. subcell in HO of intra-BSC Optimization Results

UL OL

congested idle System optimization Congestion Ass-Succ

idle congested UL Congestion Ass-Succ HSR

SummaryCell Parameter Sett ing

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Parameters for Concentric Handover

ParametersRecommended

ValueDetails

OL to UL HO

received level

Thrsh.

20~30

1.The parameter is DL RxLev.

2.Keep at least 10dB difference between OL to UL HO received level Thrsh

and UL to OL HO received level Thrsh in order to avoid Ping Pong HO.

UL to OL HO

received level

Thrsh.

30~40

1.The parameter is DL RxLev.

2.The value should be greater than Assign-Optimum-Level

Thrsh. ,because the difference between uplink RxLev and downlink RxLev.

Optimization of concentric handover

Issues of Co-BCCH Cell

Optimization Strategy

Optimization ResultsUL to OL HO

received level

Thrsh.

OL to UL HO

received level

Thrsh

UL is congested, OL is idle Congestion HSR DCR

UL is idle, OL is congested

Congestion HSR DCR

UL >OL HSR is low

HSR DCR

OL >UL HO times is low, DCR is high

Congestion HSR DCR

OL>

UL HSRs are low.

Congestion HSR DCR

SummaryCell Parameter Sett ing

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2. Have to constantly adjust handover parameters to minimize inter-layer

handovers (different cells have different RF environment, morphologyand traffic load).

Solution : For a period Operation & Maintain of COBCCH network, we

can provide formula base on traffic and Key counters.

3. When GSM900 cell experience outage (faulty BCCH TRX, faulty circuit

packs), DCS1800 cell cannot absorb the traffic (lost revenue).

Solution: Configure more than one 900M TRX in the underlay sub-cell,

if BCCH TRX fault, another 900M TRX will replace it.

Co-BCCH Introduct ion

Risk

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Restriction

Dont support different band frequency in one frequency hopping

sequence

Support GPRS in each band, but PDCH must be allocated on TRX

whose frequency band is same to BCCH

Flexibility is not so good as 900-1800 co-site cell

Co-BCCH Co-Site

Co-BCCH Introduct ion

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Thank You