2W User Manual

China Grentech Co., Ltd.

GSM1800M Wireless Broadband 2W Repeater

User’s Manual

Copyright: China Grentech, Co., Ltd. Document copyrighted by China Grentech Co., Ltd. No copying or dissemination without written approval.

China Grentech Co., Ltd. GSM1800 Wireless Broadband Repeater User’s Manual

Page 2 of 16

Preface .................................................................................................................................................................. 3

Chapter 1 Overview.......................................................................................................................................... 4

Chapter 2 Device Application .......................................................................................................................... 5

1 Expanding service area ............................................................................................................................... 5

2. Eliminating large blind-zone shadow and enhancing call quality ............................................................. 5

3. Special Landform Coverage ...................................................................................................................... 6

4. Network Optimization ............................................................................................................................... 6

Chapter 3 Design Features ............................................................................................................................... 8

Chapter 4 System Working Principles ............................................................................................................ 9

Chapter 5 System Composition ..................................................................................................................... 10

1 Major components .................................................................................................................................... 10

2 Integral Type System Composition .......................................................................................................... 10

Chapter 6 Technical Parameters and Indices ...............................................................................................11

Chapter 7 Device Installation ........................................................................................................................ 12

1 Device Mechanical Characteristics........................................................................................................... 12

2. Installation Method .................................................................................................................................. 12

3. Connection Mode .................................................................................................................................... 13

Chapter 8 Device Debugging ......................................................................................................................... 14

1.Apparatuses and tools used for testing ..................................................................................................... 14

2. Main Indices and Adjustments of On-site Debugging ............................................................................. 15

1. Receiving signal level .............................................................................................................................. 15


Page 3 of 16

Preface

This manual describes how to use, install, test, and maintain the mobile communication GSM wireless

broadband repeater SGR-R321D-2 produced by Shenzhen Powercom Co., Ltd.

Please read this manual carefully before you install and use the GSM wireless broadband repeater

SGR-R321D-2 device.

Note the following when using the manual:

1. Copying of reproduction of any part of this manual is prohibited.

2. This manual is subject to change without notice.

3. Suggestions on this manual are welcome.


Page 4 of 16

Chapter 1 Overview

As the number of urban and village mobile communication users increases constantly, there appear such

characteristics as wide service area, wide area, and dispersed users, for example, many suburbs, county

towns, towns, villages, and express highways. BTS coverage of these areas is sure to cause such

problems as heavy investments and low channel utilization. In addition, in the transmission path of

mobile communications, some natural or man-made factors (such as mountains, large buildings, tunnels,

and underground facilities) make communication very difficult.

Powercom’s SGR-R321D-2 GSM 1800M repeater is an economical and reasonable solution designed

specifically for solving the above-mentioned problems. The SGR-R321D-2 GSM repeater can

implement linear amplification on the received weak mobile communication signals, forward the signals

to the service area through the retransmission antenna. It also receives, amplifies, and retransmits the

signals of the MSs in the service area to the BTS, thus implementing the signal repeating and

retransmission and satisfying signal of the specific areas by using the directionality of the retransmission

antenna. Using the highly selective surface acoustic wave filter, the GSM wireless broadband repeater

system features excellent out-band selectivity. In combination with the linear power amplification

technology, it guarantees the strict linearity indices of the GSM and has the advantage of being more

stable and secure over the earlier repeater systems.


Page 5 of 16

Chapter 2 Device Application

Featuring such characteristics as high selectivity, high gain and high power, the SGR-R321D-2 GSM

1800M repeaters are widely used.

1 Expanding service area It is well known that the propagation distance of the wireless signal in the air is affected by transmission

power, reception sensitivity, land form, topographical features, and other factors. The SGR-R321D-2

GSM repeater can receive, amplify, and retransmit the RF signals from the BTS or the user's mobile

phone to expand the coverage area and fully utilize the existing channel resources. Depending on the

actual contrition, this expansion can be targeting, thus greatly reducing the cost of BTS construction,

This is shown in Figure 1.

BTS

Mobile user

Original coverage

area

Expanded coverage

area

Repeater

2. Eliminating large blind-zone shadow and enhancing call quality Complicated landforms, topographical features, high mountains, or high buildings cause signal weak

zones or bland zones. The SGR-R321D-2 GSM repeater can “guide” the signals to these areas and

transmit the MS signals to the BTS, thus readily solving the problem.

See the following figure:


Page 6 of 16

3. Special Landform Coverage The coverage surfaces of such special situations as express highways and railways are generally

ribbon-shaped. In tunnels, deep under the ground in mines, and in hillsides, the coverage directionality is

obvious. Under this condition, the SGR-R321D-2 GSM series repeater can easily implement fixed-point

and directional coverage of the signals, which is very convenient.


4. Network Optimization The SGR-R321D-2 GSM repeater can solve the coverage problem among the neighboring service cells,

implementing the function of patching blind spots and ultimately implementing the seamless coverage of

the mobile communication signals.



Page 7 of 16


Page 8 of 16

Chapter 3 Design Features

• Using the medium-frequency surface acoustic wave to select bandwidth; having the advantage of

being more stable than other repeater systems.

• Having the antenna isolation auto detection and gain auto setting functions to prevent self-excitation

and ensure the device operates reliably

• Using the RS-232 communication interface, capable of transmitting data through the PSTN and GSM

network; the monitoring measures are diversified.

• Having the unique mobile phone SMS monitoring function and the portable “NM center” for the

convenience of network maintenance.


Page 9 of 16

Chapter 4 System Working Principles

The GSM wireless broadband repeater system uses the square eight-stack RF filter technology, improves

the input SWR and linearity index of the low-noise module based on the original low-noise technology,

and repeats and forwards the air wireless transmission GSM signals to implement signal coverage of the

blind zones. The device couples the GSM signal to be amplified in the air. After the GSM signal enters

the device, the signal is filtered through the duplexer, enters the low-noise amplifier and the

frequency-selective module, is amplified by the power amplifier and is transmitted through the antenna,

When designing the circuits, design the low-noise amplification module and the power amplification

module, respectively. Each module is elaborately designed and strictly tested to ensure reliable and

stable device performance. There are power control circuits in all amplification modules to ensure the

security of the device. Modularized design solution makes device maintenance and upgrading very

convenient. In addition, with the elaborately designed monitoring and alarm circuits, the user can have

complete control over the working status of the device remotely.

The number of the wireless band selective integral type is SGR-R321D-2. Its work principle is shown in

the following figure:

GSM Band Selective Repeater Work Principle


Page 10 of 16

Chapter 5 System Composition

1 Major components 1. Donor antenna (facing the BTS direction)

2. Retransmission antenna (facing the direction of MS)

3. Host (integral type)

4. RF coaxial cable

5. Power distributor (optional for multi-point coverage)

2 Integral Type System Composition


Page 11 of 16

Chapter 6 Technical Parameters and Indices

The technical indices of the SGR-R321D-2 are as follows:

Test item Indices

Forward-link Reverse-link Frequency range 1855 ~ 1870 MHz 1760 ~ 1775 MHz Maximum output power 33dBm (0dB/-2dB) 23dBm(0dB/-2dB) Automatic Level Control (ALC) Yes Yes Gain 82±3dB 82±3dB Gain adjustment range ≥30dB ≥30dB Gain adjustment step 1dB 1dB In-band fluctuation ≤3dB ≤3dB Noise coefficient ≤4dB ≤4dB Voltage SWR ≤1.4 ≤1.4 Delay ≤5.0µs ≤5.0µs

Out-band net gain

±400KHz ≤50dB ≤50dB ±600KHz ≤40dB ≤40dB ±1MHz ≤35dB ≤35dB ±5MHz ≤25dB ≤25dB

Out-band Spurious radiation

9KHz-1GHz ≤-36dBm ≤-36dBm

1GHz-12.75GHz ≤-30dBm ≤-30dBm

Inter-modulation attenuation ≥ 50 dBc/30 KHz (dual tone

interval 600 KHz, combiner full power)

≥ 50 dBc/30 KHz (dual tone interval 600 KHz, combiner full

power)


Page 12 of 16

Chapter 7 Device Installation

1 Device Mechanical Characteristics The device uses the sheet-metal structure.

Integral device:

Length (mm) Width (mm) Height (mm) Weight (Kg) 690 471 230 34

2. Installation Method Method 1:

Fix the device on the outdoor wall. The installation is shown in the following figure:

Approved by

Liu Zeyu 2002.

Document No.

Wall Repeater

4-M18 expansion

Processed by

Standardized by

Reviewed by

Designed by

Quantity Date Signature Changing

mark

Project Installation

Schematic Drawing

Shenzhen Powercom Co., Ltd.

Page of

Sample mark Quantity Scale

screw bolt; 50 ~ 70 mm long;with several flatshims and spring washers

Installation procedures:

1. On the selected device installation site, punch holes in accordance with the bracket hole positions and

install expansion screws (specification: φ10 × 8).

2. Referring to installation method 1, fix the repeater bracket on the wall or the mast.

3. Referring to installation method 1, place the repeater on the bracket and fix it.

4. Referring to the connection mode, connect the cables with the device.


Page 13 of 16

3. Connection Mode The device connection panel is shown in the following figure:

Power indicator Retransmission end

Power supply

Retransmission end


Page 14 of 16

Chapter 8 Device Debugging

Device debugging Depends on the situation of the on-site isolation (to prevent self-excitation), set the

frequency selective module uplink (downlink) gain to the required gain value ,For details, see the

description of the NM system.)

1.Apparatuses and tools used for testing Name Specification Quantity Remarks

Spectrum analyzer (with source) able to cover 1 GHz 1

VSWR tester 1

Test cables 3 1.5 meters long

Attenuator 30dB, 20 dB .10 dB.5dB 1

Coupler 30dB,10dB 1

Conversion connector male ,female different types of N, SMA each one for 3.

BNC-N connector 2 (for 5011 type spectrum analyzer)

Power supply tieline 1

Digital multi-meter 1

Box spanner 1 (for opening box cover)

Spanner 1

SMA Spanner 1

Screwdriver cross-shaped straight-slot 1 (large-size)

Small screwdriver straight-slot 1 (for puling the switch)

Waterproof adhesive tape 1

Bandage 1

Silica gel 1

In-line antenna 1

Small-sized antenna (ceiling mount) 1

Measuring tape 1


Page 15 of 16

2. Main Indices and Adjustments of On-site Debugging 1. Receiving signal level

The signal level received through the donor antenna should not be over -45dBm; otherwise, use an

attenuator to adjust the signal to be lower than -45dBm. If the received signal level is below -70dBm, the

output power may be unable to reach the expected output value, normally ours advice of input is about

-50dBm.

2. Isolation Detection

Add a signal with the strength of XdBm on the retransmission antenna end. Suppose the same signal is

detected on the donor antenna end and its strength is YdBm. Then the system isolation is I = X-Y

(dB)For example, if X=10dBm, Y=-90dBm, then I=100dB. And repeater’s gain is no more than I-15dB,

it’s 85dB, this is both for uplink and downlink. If the signal cannot be detected on the donor antenna end,

the isolation should be estimated at 100 dB.

3. Downlink (Forward-link) Signal Debugging

The downlink signals amplified by the repeater should not suffer distortion and reach the designed power

output at the output interface. The maximum full power output designed by this device should not be

over 40 dBm (10W). For normal working, set it to 37 dBm (5 W) to prevent overload when there are

many subscribers suddenlly. Actual output power depends on the input signal and downlink gain. The

maximum downlink gain value, GDOWN, is acquired through the formula, GDOWN =I-15 (dB). Actual

downlink gain GD should not be set to be greater than GDOWN .

4. Uplink (Reverse-link) Signal Debugging

After being received by the repeater, mobile phone signals not in the BTS coverage area can be

forwarded to the BTS. The maximum uplink gain can be acquired from the following formula: Gup

=GDOWN –3. Actually, uplink gain Gu should not be set to be greater than Gup.(In some cases, the

difference can be 5dB. )

Uplink and downlink gain must be adjusted synchronously to maintain the uplink/downlink balance.

5. Self-excitation Signal

If the repeater gain is set incorrectly or there is not enough isolation between the donor antenna and the

retransmission antenna, self-excitation easily occurs. Self-excitation signal is a signal that changes in

great amplitudes in the in-band frequency and easily blocks the corresponding BTS and burns the device.

Therefore, it must be controlled strictly in the debugging.

The effective solution to eliminate self-excitation is to lower gains. Adjust antenna installation location

and direction. Increase isolation.


Page 16 of 16

6. Device Checking

If signal reception or transmission channel is abnormal and it is difficult to determine the fault cause,

the spectrum analyzer detection device with scanning source (For device indices, see device

instruction manual.) Note that the amplitude of introducing signals should accor

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