“OpenBTS Development Kit”

Specifications, Installation & Operation

Doc. Rev. 1

Copyright c©2013 Range Networks, Inc.

All rights reserved

Contents

1 Introduction 6

1.1 Scope and Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.2 Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.2.1 Errors and Future Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.2.2 Radio Interference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.3 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

1.4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.5 Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Specifications 8

2.1 Mechanical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.1.1 Package Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.1.2 Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.2 Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.3 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.4 RF Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.4.1 RF Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.4.2 RF Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3 BTS Operation 12

3.1 Installed Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.2 Source Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.3 Initial Power-Up Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.4 System Access and Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.5 Accessing the OpenBTS Console . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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CONTENTS 3

3.6 “Safe” GSM Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.7 Initial Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

List of Figures

2.1 OpenBTS Development Kit front panel mechanical. . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2 OpenBTS Development Kit side view mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . 9

4

List of Tables

2.1 OpenBTS Development Kit mechanical dimensions. . . . . . . . . . . . . . . . . . . . . . . . . 9

2.2 OpenBTS Development Kit environmental specifications. . . . . . . . . . . . . . . . . . . . . . 10

2.3 RF operating ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

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Chapter 1

Introduction

1.1 Scope and Audience

This document describes the physical specifications and initial installation of the Range Networks OpenBTSDevelopment Kit (part number 2115-001) equipment. This manual does not cover full unit configuration or anysignificant aspects of GSM/VoIP operation. For those topics, see the OpenBTS software manual.

This document is intended for use by researchers, developers, and laboratory specialists. It assumes a generalfamiliarity with the Linux operating system and IP networking.

1.2 Disclaimers

1.2.1 Errors and Future Changes

Although the information in this manual has been carefully checked for accuracy, and is believed to be correctand current, no warranty, either express or implied, is made as to either its applicability to, or its compatibilitywith, specific requirements; nor does Range Networks, Inc. assume any responsibility for correctness of thisinformation, or for damages consequent to its use. All design characteristics, specifications, tolerances, and thelike are subject to change without notice.

1.2.2 Radio Interference

Operation of improperly configured cellular equipment can result in interference to existing services, possiblyinterrupting public networks and public safety systems, even though the output power of the OpenBTS Devel-opment Kit is relatively low. Range Networks, Inc. cannot insure that any of the procedures in this manual willnot result in radio interference to other services and networks.

1.3 Abbreviations

• ARFCN – absolute radio frequency channel number

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1.4. REFERENCES 7

• dBm – decibel milliwatts

• MS – mobile station (cellular phone or handset)

• RF – radio frequency

• VDC – Volts, direct current

1.4 References

This document references the following GSM specifications, which can be downloaded for free from http://webapp.etsi.org/key/queryform.asp

• GSM 03.40: “Digital cellular telecommunications system (Phase 2+); Technical realization of the ShortMessage Service (SMS) Point-to-Point (PP)”

• GSM 04.08: “Digital cellular telecommunications system (Phase 2+); Mobile radio interface layer 3specification”

• GSM 05.05: “Digital cellular telecommunications system (Phase 2+); Radio transmission and reception”

• GSM 05.08: “Digital cellular telecommunications system (Phase 2+); Radio subsystem link control”

1.5 Contact Information

For additional information or products referenced in this manual, please contact:

Range Networks, Inc.560 Brannan StreetSan Francisco, California 94107United States of America

telephone +1 415-778-8700

email support@rangenetworks.com

Chapter 2

Specifications

The OpenBTS Development Kit consists of:

• a mini-ITX computer with 8GB mSATA flash drive, and 2GB RAM,

• a Range Networks ”RAD1” wideband digital radio,

• a +12V, 5A power supply with a power cord,

• two multi-band rubber duck antennas.

• two pre-programmed SIM cards,

• two test phones.

2.1 Mechanical Specifications

The computer and the radio are packaged in a desktop enclosure. The Range Networks Rack Mounting Brackets(part number 8710-000-0) are available separately and allow you to mount your OpenBTS Development Kitonto your existing rack (1U, 4.45 cm / 1.75”).

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2.1. MECHANICAL SPECIFICATIONS 9

Figure 2.1: OpenBTS Development Kit front panel mechanical.

Figure 2.2: OpenBTS Development Kit side view mechanical.

2.1.1 Package Dimensions

Figures 2.1 and 2.2 show front and side views with all measurements marked in inches and millimeters. Themechanical dimensions are given in Table 2.1. Range Networks units use standard metric-sized Phillips-head(crosspoint) fasteners throughout.

Table 2.1: OpenBTS Development Kit mechanical dimensions.

Dimension Value Comments

width 30.48 cm (12”)

height 4.45 cm (1.75”) 1U in optional rack mounting brackets

depth 25.40 cm (10”)

min. front clearance 5.08 cm (2”)

min. rear clearance 5.08 cm (2”) ventilation

min. side clearance 3.81 cm (1.5”) ventilation

min. top clearance 0 cm (0”) touching OK

min. bottom clearance 0 cm (0”) touching OK

weight 1.5 kg (3.3 lbs) unit only

Starting from the left and moving across, the items on the OpenBTS Development Kit front panel are:

• Power switch with a LED indicator above it,

• “KEY/SSD” – USB socket for reset dongle or removable media drive,

10 CHAPTER 2. SPECIFICATIONS

• “ETHERNET” – Ethernet connector (RJ-45 socket),

• “Rx” – receive-side RF connector,

• “Tx” – transmit-side RF connector.

2.1.2 Ventilation

Do not block the OpenBTS Development Kit unit on the sides, as they contain the ventilation openings. Theunit does not require forced air cooling.

2.2 Environmental Specifications

Table 2.2 gives the environmental requirements for the OpenBTS Development Kit. The OpenBTS DevelopmentKit is designed for indoor use, either in a desktop or a rack-mounted installation. However, the unit should notrequire refrigeration, even in the warm climates.

Table 2.2: OpenBTS Development Kit environmental specifications.

Parameter Allowed Range

operating temperature TBD

operating humidity 5% to 95%, non-condensing

shock and vibration normal truck transport

2.3 Electrical Specifications

The OpenBTS Development Kit takes a 12V, 5A DC power supply.

2.4 RF Specifications

The OpenBTS Development Kit is a multi-band unit that can be used in any of the four standard GSM bands:GSM850, EGSM900, DCS1800, PCS1900. It does not include any band-specific filtering in the transmitter orreceiver.

2.4.1 RF Output

The OpenBTS Development Kit features the Range Networks ”RAD1” wideband digital radio and has themaximum output power of 100 mW (20 dBm). The actual output level is controlled by the software.

On any given ARFCN, the output bandwidth is 270.833 kHz. The spectrum mask is verified to comply withGSM 05.05 Appendix A. All noise emissions in the downlink band are at least 50 dB below the main signal.

2.4. RF SPECIFICATIONS 11

Table 2.3: RF operating ranges

Band Receive Range Transmit Range

GSM850 824-849 MHz 869-894 MHz

EGSM900 880-915 MHz 925-960 MHz

DCS1800 1710-1785 MHz 1805-1880 MHz

PCS1900 1850-1910 MHz 1930-1990 MHz

2.4.2 RF Input

The OpenBTS Development Kit unit can demodulate GSM signals down to a power level of -110 dBm at theRF connector across its entire receive band. The receiver frequency range is given in Table 2.3.

Chapter 3

BTS Operation

In normal operation, there are two interfaces to the OpenBTS Development Kit:

• the Ethernet interface, for backhaul and administrative access, and

• the air interface, Um, for subscriber services.

3.1 Installed Components

The OpenBTS Development Kit comes with the following components installed and preconfigured:

• public release of OpenBTS – the GSM stack from layer 1 forward error correction up through layer 3;

• Transceiver – the software-defined radio,

• sipauthserve – the SIP registration proxy;

• SubscriberRegistry – the subscriber registry database;

• smqueue – the SMS store and forward server; and

• Asterisk – the SIP softswitch.

Note: As of October 2013 OpenBTS version P3.1.3 is installed on all OpenBTS Development Kit systems.

3.2 Source Code

The unit also comes equipped with the latest public release source code for the following software components:

• OpenBTS,

• smqueue,

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3.3. INITIAL POWER-UP PROCEDURE 13

• sipauthserve, and

• RRLP aiding server.

The source code is located on the file system under “/home/openbts/software/”. All of the source codedirectories are installed as SVN working directories, linked to the official public release repository. Any of themcan be updated using “svn update” command on the command line.

3.3 Initial Power-Up Procedure

1. Place the unit on your desk, or install it in a rack nearby. The test phones must be located within 6-20feet (2-7 meters) of the unit, preferably within the line of sight.

2. Attach the provided antennas to the transceiver (Tx) and receiver (Rx). The receiving antenna must bepositioned at an angle of 90◦ to the transmitting antenna.

3. Power up the unit. It takes up to 3 minutes to load the operating system and all the applications.

3.4 System Access and Control

The OpenBTS Development Kit runs Ubuntu Linux operating system. The primary interface to the unit is theUNIX shell, accessed via ssh from the Ethernet connector on the front panel. The unit’s Ethernet interface isauto-sensing, requiring no hub or crossover cable. It is shipped with the default IP address of 192.168.0.21.

Once the unit is connected to another computer or a network on the 192.168.0.x subnet, it can be accessed viassh using “openbts” account name with password “openbts”. The account is sudo-enabled. The command toissue on any UNIX system, including OS X, is:

ssh openbts@192.168.0.21

From a Windows machine, an SSH client, like PuTTY, can be used.

Note: Make sure to change the password for user “openbts” before you connect the OpenBTS DevelopmentKit to the public network.

In order to reboot the unit, type the following command at the UNIX command line prompt:

sudo reboot

Following the reboot, OpenBTS and its related services will start automatically. This process takes about 3minutes.

3.5 Accessing the OpenBTS Console

OpenBTS command line interface (CLI) is used to access (or “attach to”) the running OpenBTS software. Login to the unit via SSH as user “openbts” and type the following at the command line:

14 CHAPTER 3. BTS OPERATION

cd ~; ./CLI

To exit the command line interface, type “quit” and hit “Return”. Doing so does not stop the OpenBTSsoftware. Refer to the OpenBTS software manual for instructions on how to access and modify the OpenBTSsettings and runtime information.

3.6 “Safe” GSM Configuration

The OpenBTS Development Kit is preset with the initial “safe” configuration. Before engaging up the unit,be sure that the OpenBTS configuration is compatible with the surrounding GSM networks so as to preventdisruption of service for existing cells. At a minimum, confirm appropriate values for the following parameters:

• GSM.Identity.MCC – mobile country code. Set to 001.

• GSM.Identity.MNC – mobile network code. Set to 01. The MCC/MNC tuple uniquely identifies a mobilephone operator/carrier. 001/01 is traditionally used for test networks.

• GSM.Identity.BCC – base station color code. Should not match the BCC of any nearby cell.

• GSM.Radio.Band – operating band. Should be 850, 900, 1800 or 1900.

• GSM.Radio.C0 – radio channel number. Should be appropriate for the operating band in use, and notconflict with any cell in the surrounding area.

• GSM.Radio.ARFCNs – number of ARFCNs to use. Set to 1.

• Control.LUR.OpenRegistration – Be sure this is NULL.

• Control.LUR.UnprovisionedRejectCause – cause code to report for failed location updates. Should be setto 0x04 “IMSI not in VLR”.

• GSM.RACH.AC – access classes. Should be set to 0x0400 to indicate no support for emergency calls.

• GSM.Radio.PowerManager.MinAttenDB – minimum output attenuation. This parameter limits the max-imum output power of the unit. The value is an attenuation, so the bigger it is, the less the maximumoutput power. For initial testing, use a value of 20. Because the OpenBTS Development Kit has no up-link/downlink isolation, increasing the power output will usually result in poor performance and reducedcoverage.

This is not necessarily a configuration that you will use in your lab, but this set of parameters will minimize thelikelihood of interference with existing services while the unit is tested and configured. See the correspondingsoftware manual for further information.

3.7 Initial Testing

The default OpenBTS Development Kit configuration provides several tests that can be run independently ofthe network, with no backhaul:

3.7. INITIAL TESTING 15

1. location updating test,

2. mobile-originated loopback test,

3. mobile-originated call,

4. mobile-terminated delivery of SMS, with and without a parallel call, and

5. autoprovisioning of an handset via SMS.

See the “Quick Start Guide”, and the “Test Procedures” chapter in the corresponding software manual fordetailed description of these test procedures.

Document History

Date Doc. Rev. Changes

14 August 2013 0 working draft

4 October 2013 1 First revision

28 October 2013 2 Initial release revision

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