GSM Dual Band Network Optimization (Later Could Be Deleted)

 

双频网络规划优化 GSM移动事业部网络规划优化部 郑 浩    

 

 

 

Contents Concept Of Dual Band Network Dual Band Network Organization characteristic Dual Band Network Construction Introduction To Dual Band Wireless Parameters Traffic Control Strategy ZTE 1800M Products ZTE GSM1800 Typical Market Share

 

Concept GSM900&GSM1800 Co-exist Network ：  GSM900M&DCS1800M at a certain level are adjacent cells Two cell can Handover, Re-select naturally GSM1800

GSM900

＝ 

GSM1800

＋   GSM900

 

Differences & similarities Between GSM900 & DCS1800 •  similar network structure •  similar speech coder

• Different Frequency range

modulation •  similar technique •  similar signal protocol •  similar frequency

wireless • Different propagation rule

planning tools •   .........

• Different coverage Range • Different Transmission power •  .........

 

Contents Concept Of Dual Band Network • Dual Band Network Organization characteristic

• Dual Band Network Construction • Introduction To Dual Band Wireless Parameters • Traffic Control Strategy • ZTE 1800M Products • ZTE GSM1800 Typical Market Share

 

Development  Network Capacity Development

 

Dual Band Network Design Single Band MS

GSM9

Si

Du

ng

al

le ba

Ba nd

nd

ne tw

GSM18 DCS 1st Priority

Dual band MS

or k

 

Dual Band Network Organization Mode

GSM 900 site Continuous coverage DCS 1800 site

Discontinuous coverage DCS 1800 site

 

Dual Band Network Organization Mode MSC 900

MSC 1800

MSC

MSC

MSC

受BTS设备限制：  BSC 900

BTS 900

BSC 900

BSC 1800

BTS 900

BTS 1800

GSM900/DCS1800 Separately used MSC 注： 

900

BSC 1800

BTS 1800

GSM900/DCS1800 Shared MSC

1800 900MHz equipment

BSC

BSC

BTS 900

BTS 1800

GSM900/DCS1800 shared MSC+ BSC

1800MHz equipment

BTS 900

BTS 1800

BTS 900/1800

GSM900/DCS1800 Shared MSC + BSC + BTS  

 

Establishment of Dual Band  Network Standard • E T S I published GSM / DCS TCTR (Technical Committee Technical Report) in June 1995

 

 Network Support MSC process Class Mark 3 ( CM3 ) information CM3 information sent during call establish/ handover

MSC

BSC

BSC

GSM900

DCS 1800

BTS

BTS

 

Class Marks Power class

GSM 900 Maximum output  power

DCS 1800 Maximum output power

1 2 3

-- ---8 W (39 dBm) 5 W (37 dBm)

1 W (30  30 dBm dBm)) 0.25 W (24 dBm) 4 W (36 dBm)

4 5

2 W (33 dBm) 0.8 W (29 dBm)

Tolerance (dB) for conditions normal extreme 2 2 2

2.5 2.5 2.5

2 2

2.5 2.5

 

Class Marks

 

Ideal Dual Band Network Requirements Ms can Room /support between two different Bands Ms Can Handover Between two bands Traffic Well Bala Balanced nced Between the Dual Bands

Proper cell reselection and location update By ensuring speech quality, Dual Band Network has to reduce unnecessary handovers Reliable error correction

 

Contents Concept Of Dual Band Network Dual Band Network Organization characteristic Dual Band Network Construction Introduction To Dual Band Wireless Parameters Traffic Control Strategy ZTE 1800M Products ZTE GSM1800 Typical Market Share

 

Wireless propagation Characteristics • 1800& 900 have different propagation characteristics. 1800 has higher path loss, about 6-12dB higher than 900. usually around 9dB ； 

 

Link budget-example Downlink,from BTS to MS 

Uplink,from MS to BTS 

BTS TX Power Combining Loss Duplexer Loss Top of cabine cabinett TX power Feeder Loss BTS antenna gain Total EIRP

42 3 0 39 2 18 55

MS RX sensitivity MS antenna gain Fading margin Interference margin Antenna body loss MAX.allowable path loss 

dBm dB dB dBm dB dBi dBm

MS TX Power MS Antenna gain Total EIRP

30 dBm 0 dB 30 dBm

Feeder Loss BTS antenna gain

2 dB 18 dBi

-100 dBm 0 dB

BTS RX sensitivity Diversity gain

-104 dBm 5 dB

6 dBm 3 dBm 3 dBm 143 dB 

Fading margin Interference margin Antenna body loss MAX.allowable path loss 

6 dBm 3 dBm 3 dBm 143 dB 

Link Balance(Downlink-Uplink)=0 

 

Coverage • According to ETSI suggestion：From coverage point of view, 1800M has about 9dB loss more than 900M, below is the detailed coverage table： table ：  Used freque ncy

Allowed  pass loss （dB） 

（ MH z） 

sensitivity （dBm） 

Typical cell radius （ km ）  Propagati on model used

BTS

MS

Village illa ge and other open areas

Urban area

900

134

-104

-102

19

3

Hata

1800

143

-104

-100

7

1

Cost231Hata

 

construction suggestion  Network construction • According to dual band network propagation model Principle Dual Band Network Planning GSM900 ensures coverage, DCS1800 takes care of traffic

DCS1800 site Layout Choose the site with already existing GSM900 system in order to use the already al ready existing equipment like; tower, room, power etc and serve on the investment

Antenna installation DCS1800 antenna better be 2-3m higher than GSM900 antenna Two systems antenna system azimuth angle needs to be the same to control traffic Horizontal and vertical angle needs to be small and close

DCS1800 gain should be 2-5dBi more than GSM900 or equal  

Contents Concept Of Dual Band Network Dual Band Network Organization characteristic Dual Band Network Construction Introduction To Dual Band Wireless Parameters Traffic Control Strategy ZTE 1800M Products ZTE GSM1800 Typical Market Share

 

Introduction to Wireless ParametersCell Selection •

Cell selection when MS is switched on or is from the area without service and has entered into the area with coverage service synchronizes

ms monitors the signal from the cell and

scans different cells BCCH channel and choose the suitable cell

according to cell selection precedence  and C1>0 

according to cell selection C1 and precedence value, ms

select the cell and the cell becomes the serving cell

 

Introduction to Wireless parameters －C1 Rule C1 = A- M ax(    MS_TXPWR_MAX_CCH  –   P    ,0) • A=Received Level Average- RXLEV_ACCESS_MIN；  • P =MS maximum RF power output ；  • Unit for the above parameters is dBm。  • C1>0 satisfies standard path loss

 

Introduction to Wireless parameters －CBA、CBQ • If a certain cell CB CBQ Q ,CBA is set to (0,0), then this cell during cell selection has ordinary Precedence if certain cell CBQ, CBA is set to (1,0) or (1,1), then this cell has lower  Precedence  Precedence。  CellBarQualify

CellBarAccess

Cell

selection

Precedence

Cell

reselection

status

0

0

Normal

Normal

0

1

Barred

Barred

1

0

Low

Normal

1

1

Low

Normal

 

Introduction to Wireless Parametersexample:1800M Precedence • In order for MS to first select 1800M, 1800M cell has to be set as a normal precedence cell, with: CBQ=0, CBA=0; 900M cell set to lower precedence cell, its CBQ=1, CBA=0 900M Cell：CBQ = 1，CBA = 0，C1=15 C1=15  

1800M Cell Cell： ：CBQ = 0， 0，CBA = 0， 0，C1=10 

Switched on selecting a cell

 

Introduction to Wireless Parameters －C2 Rule C2 = C1 + CRO  –   TO C2 = C1  –   C R O ，  

H PT  –   T) PT    3 1 PT=31   PT=31 

• CRO = CELL_RESELECT_OFFSET ；  • TO = TEMPORARY_OFFSET ； 

•  PT = PENALTY_TIME ，20s,40s,... • T ， MS Timer •  For Non service cell H(x) = 0， x