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Drilling Platform GSM&WCDMA Indoor Signal Distribution System

2014-9-1 17:46:55

1、Project overview


1、Basic information of project sites
The oil drilling platform is located in ***. There are * floors need to be covered totally. After the survey with ship-owner, we confirm that: for the platform location and metal structure, the wireless signal will be shielded, which will affect the users’ phone call on the platform. 
Therefore, we give this project to solve the phone signal coverage problem. In the system, the antenna feeder system is conforming to 3G and WLAN requirements.

2、Customer contact way

3、Basic information of electromagnetic environment
Test list of GSM900 signal current situation
 

feature

China Mobile

China Unicom

Floor

Proportion

Function

Signal intensity

Area No.

Conversation quality

Remark

Signal intensity

Area No.

Conversation quality

Remark

1F

 

 

-9X

 

Can’t connect

G net

 

 

 

 

Well drilling platform is belonging to operation platform. Because of the distance is far from the offshore base station, sell phone mobile signal is weak which has bad influence for the users’ phone use. Therefore, it’s very important to build a system for GSM900 mobile signal coverage.
4、Coverage and purpose
According to the survey of the platform and requirements of ship-owner, we will make GSM900, CDMA, WCDMA mobile signal coverage on deck. No connection Phones caused by weak signal will be solved.

2、Basis of design

(1)、Basis of design
1、 issued by Ministry of health of the People’s Republic of China
2、Ministry of posts and telecommunications<900MHz TDMA Digital Public Land Cellular Mobile Communication Network Technology System> (T2019-95)&
3、CCITT and GSM900ETSI standard;
4、Posts and Telecom Press;Mobile communication design•
5、Nong zhang • mobile communication design
6、William C.Y Lee’s mobile communication design theory.
7、William G.Duff.Handbook on Mobile Communications;
8、The platform owners’ requirements.

(2)、Principles of design
1、Ensure the excellent coverage effect, decrease the project cost.
2、Use the signal from base station adequately, decrease the noise if
Possible.
3、Considering the environmental problem, increase the antenna and
decrease the output power.
4、Consider the antenna quantities, position, output power and coverage
to ensure the signal’s equal distribution
5. integrated the building structure, function and decoration, distribute antenna and feed line system reasonable. 

3、Thought of design


1、Confirmation of signal source and equipment model
Indoor signal distribution systems are GSM, CDMA, and WCDMA. GSM includes China Mobile and 2G signal. WCDMA is China Unicom 3G signal.
A、Signal source confirmation
After the field survey, on the top of platform, ISP’s cellular as signal source, amplified by repeater; the platform will be covered finally. Signal source specifications are:
GSM900 signal source as below:
 

 

Master station name

 

BCCHoperation frequency

 

Master LAC

 

Master CID

 

Distance (km)

 

Receiving signal field intensitydBm

 

Frequency hopping way

 

B、Equipment confirmation:
This design project utilizes wireless access RF to forward indoor signal distribution system. And the repeater will be the master signal source for the mobile signal coverage on the platform.
C、Set the field intensity of edge
GSM system
For the signal in coverage area are weak or no signal, this project should increase the signal, the field intensity of edge is set to equal or more than -80dBm
WCDMA system
According to the ship-owner’s requirements, integrated the actual situation of platform, the deck area will be satisfied the VOIP, the field intensity of edge is set to:Ec≥-90dBm,Ec/Io≥-12dB(guarantee PS64K、CS64K、CS12.2K)
2、Coverage way
The whole coverage area will be covered with one set of antenna feeder system.
After the simulation test, GSM900 analog signal output power as a reference, and then we can know the antenna distribution position.
The signal in deck area is very weak, to ensure the signal coverage effect and the signal can be 3G in the future. We install ** ceiling antenna, **glass fiber reinforced plastic Omni-directional antennas. The antenna installation picture is:

3、Confirmation of antenna model
In this project, all the ceiling antennas are wide frequency antenna (model ***)

4、Analysis of project design


1、Predication analysis of coverage area’s field intensity
According to the tests we made in other areas, each frequency band signal loss in the building are:
The lowest signal field intensity is:
RSSI-antenna power rate + antenna gain - space loss - cover loss - multiple way loss
 =11.8+2.1 dBi-57dB-15dB-10dB
    = -68.1dBm
2、Analysis of coverage effect
After the calculate results, all systems in the project are satisfied the field intensity requirements. The system will not be affected by outside network through the reasonable setting of signal source frequency and controlling of signal interference. According to the above analysis, the field intensity weak point is in the overlapping area of antennas.
3.Signal to noise ratio analysis of the system
The noise will be increase between base station and repeater for the repeater.
4.Up and down balance analysis of the system
If there is no balance of Up and Down, especially the up link loss is strong than down link loss, cell-phone will has strong signal, but cell-phone can not be two-way communication.
This indoor signal distribution system is the antenna feeder system with integrated passive and active systems, the up link and down link loss is same.
5.Communication traffic prediction analysis
Communication traffic prediction of platform(ERL):
= Construction area×75%×1/20×20%×0.01(75% is practical area;1/20 is office area;20% is cell-phone own ratio ,0.01 communication traffic)
=2000×75%×1/20×20%×0.015=0.2ERL
The indoor signal distribution system-GSM900 carrier can be satisfied communication traffic.
6. Compatibility analysis
Antenna frequency is 800~2500MHz;
Power divider frequency is 800~2500MHz;
Coupler frequency is 800~2500MHz;
7、Features analysis
A. Considering it is indoor signal coverage, we utilize signal source output power. In order to improve the performance, we use the coupler and power distributor to distribute power.
B. The project is made by our field survey, simulation test, the antennas are distributed reasonable. And we take GSM900 signal distribution as a reference. Therefore, all the areas will be covered effective.
8、Project scale
The indoor signal distribution system covers deck of the platform, totally we use * pcs ceiling antenna and *pcs glass fiber reinforced plastic Omni-directional antennas.

 5、Equipments Specifications
1、The Major equipments list

Item NO.

Name

Model

Factory

1

GSM900 repeater

 

ANYKEY

2

CDMA800 repeater

 

ANYKEY

3

WCDMA repeater

 

ANYKEY

4

GSM900 repeater

 

ANYKEY

5

Ceiling Antenna

 

ANYKEY

6

Yagi Antenna

 

ANYKEY

7

Planar Antenna

 

ANYKEY

8

Coupler

 

ANYKEY

9

Coupler

 

ANYKEY

10

Coupler

 

ANYKEY

11

Coupler

 

ANYKEY

12

Coupler

 

ANYKEY

13

Two-way power divider

 

ANYKEY

14

Three-way power divider

 

ANYKEY

15

Four-way divider

 

ANYKEY

16

Feeder line

N-7/8

 

17

Feeder line

N-1/2

 

18

Joint

N-J-7/8

ANYKEY

19

Joint

N-J-1/2

ANYKEY

 2、Major products specifications
GSM Indoor Repeater

Frequency band

UP: 885~909MHz

DOWN: 930~954MHz

       Gain

 

Gain adjustment range

 

Maximum input power level

 

Stray and cross modulation

 

 

Up noise value

 

pass band fluctuation

 

 

VSWR

 

Delay

 

RF joint

 

Output power rate

 

RF interface impedance

 

Operation power

 

Power consumption

 

Ambient temperature

 

Volume(length*width*height)

 

Monitoring warning

 

Remote warning function

 

Glass Fiber Reinforced Plastic Omni-directional Antennas

Electrical Specifications
Impedance
 
Frequency
 
Gain
 
Front-to-end ratio
 
VSWR
 
Polarization
 
Horizontal lobe width
 
Vertical lobe width
 
Power rate
 
Interface type
 
Mechanical Property
Unit Quantities
 
Length
 
Weight
 
Wind loading
 
 
 

 Power Divider

Application

For power distribution of indoor signal distribution system

Frequency band

 

Insertion loss

 

 

 

Impedance

 

VSWR

 

Power capacity

 

Interface type

 

Volume

 

 

 

Weight

 

 

 

Temperature

 

Humidity

 

 Coupler

Application

For power distribution of indoor signal distribution system

Frequency band

 

Insertion loss

 

 

 

Impedance

 

VSWR

 

Power capacity

 

Interface type

 

Volume

 

Weight

 

Temperature

 

Humidity

 


Feeder Line

Application

1/2″feeder line

Model

Distribute line, not use only

Distribute line,the length is not exceed 100meter

size(mm)

Inner conductor diameter

4.83

2.5

outer conductor diameter

13.8

8.7

Insulation sleeve diameter

16

10.4

Impedance(Ohm)

50±1

50±2

Working frequency limited(GHz)

>2

>2

The minimum bending radius(mm)

<70

<27

Insertion Loss (dB/100m)

900MHz

<7.2

<14

1800MHz

<10.6

<20

Operation temperature

-40℃+85℃

Whether has the flame retardant function

 

Yes

No

6、Design Specifications

1、Overall design specifications
(1) Telephone traffic: telephone traffic undertook by base station.
(2) Coverage: Distribution systems cover the deck
(3) Wireless channel call loss rate is equal or less than 2%, up and down power is balance at *db.
(4) The TX is *dBm of indoor antenna according to the national electromagnetic standard.
(5) Call loss rate is less than 1%, call success rate is more than 95%, switch success rate is more than 95%.
2.Design specifications
GSM China Mobile  Up: 875-909MHz,Down: 930-954MHz
GSM China Unicom  Up: 909-915MHz,Down: 954-960MHz
WCDMA China Unicom 3G  Up: 1940MHz-1955MHz,Down: 2130MHz-2145MHz
CDMA 800 China Telecom    Up: 825MHz-840MHz  Down: 870MHz-885MHz


7、Installation Instructions


1、Installation of major equipments
3 PCS repeaters are installed on ****, realize signal coverage ****
2、Installation of Antenna
The ceiling antenna fixed on ****, it will not affect the decoration.
3.Installation of passive components
The power dividers installed and fixed on ****.
All of the exposure feeder line should be covered with PVC. In the construction process, decoration and structure of the computer room and building should not be broken.
4. Installation of power supply device
The repeater powered from the power distribution box.
5、Instructions of other items
Both ends of the feeder line should be remarked “starting point” and “end point”. All of the devices, components should be remarked for the project inspection in future.

8、Prevention of electromagnetic radiation


According to the People’s Republic of China standard, namely GB8702-87, the limited value of electromagnetic radiation is:
Public radiation: In 24 hours, the field quantity of electromagnetic radiation within any 6 minutes, its average value should be less than 0.4W (frequency is 30-300MHz)
Professional radiation: In 8 working hour, the field quantity of electromagnetic radiation within any 6 minutes, its average value should be less than 2W/m2 (frequency is 30-300MHz)
Requirements of electromagnetic radiation exemption:
1.Mobile wireless communication equipments which output power are less than or equal to 15W.
2.When the frequency is 3-300000MHz, the output power of electromagnetic radiation body is less than 100N.
3.The strongest signal level is **dBm for this project, workers are around the antenna more than 1 meter, the strongest power rate is 0.078 W/m2, therefore, the prevention is satisfied public radiation prevention.

 9、Project Cost Budget
10、Attached Diagram


1、System schematic diagram
2、Diagram of antenna position

System schematic diagram

Diagram of antenna position


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