Building, Installing and Running OpenBTS

This document describes the installation of a single instance of OpenBTS on a single PC with a single radio. This default configurations support this setup, and it's the right place to start. For a multi-BTS environment, see this page.

If you are updating OpenBTS, please see UpdateOpenBTS.

A complete installation of OpenBTS P2.8 comprises these components:

• OpenBTS itself. This is the GSM implementation from the TDMA part of L1 up through L3 and the L3/L4 boundary. Its SIP interface is normally on port 5062. This is located in openbts/trunk.
• Transceiver. This is the software radiomodem, implementing the lower part of L1. OpenBTS starts the transceiver automatically. These are located in openbts/trunk/Transceiver*.
• A SIP PBX or softswitch (Asterisk, FeeeSWITCH, etc.) This component connects speech calls. Its SIP interface is normally on port 5060. This is not packaged with OpenBTS.
• Sipauthserver. This is the SIP registration and authorization server, used to process location updating requests from OpenBTS and perform corresponding updates in the subscriber registry database. Its SIP interface normally runs on port 5064. This is located in subscriberRegistry/trunk.
• Smqueue. This is the store-and-forward text messaging server. It needs to be started independently of OpenBTS. Its SIP interface is normally run on port 5063. Smqueue is not required in installations that do not support text messaging. This is located in smqueue/trunk.
• Rrlpserver. This is the RRLP aiding server and it is run as a CGI script in a web server. Rrlpserver is not required if RRLP is not being used. This is located in RRLP/trunk.

Getting the Code

See Where can I get the latest code?

Required Libraries/Utilities

To compile the various parts of OpenBTS (minus the PBX) you'll need the following packages:

autoconf

libtool

libosip2

libortp

libusb-1.0

g++

sqlite3

libsqlite3-dev (sipauthserve only)

libboost-all-dev

libreadline6-dev

These can be installed (on a Debian-flavored unix distro) with the following command:

sudo apt-get install autoconf libtool libosip2-dev libortp-dev libusb-1.0-0-dev g++ sqlite3 libsqlite3-dev erlang libreadline6-dev libboost-all-dev

System Diagram

In this diagram, Black links are network connections (SIP). Red links are file system connections (sqlite3 lookups). Blue links are ODBC (network/local DB lookups).

Build and Install OpenBTS and the Transceiver

Hardware

OpenBTS can be run a variety of hardware. You must first note the specific hardware being used. There are three distinct types:

• Range Equipment (e.g., RAD1?)
• Fairwaves  UmTRX (use own UHD version)
• Ettus Research USRP1 with external clock modifications and transceiver board (WBX prior to V3, RFX)
• Ettus Research UHD Devices (e.g., USRP2?, N200 Series, B100)

Building OpenBTS

OpenBTS should, in principle, build and run on any Unix-like operating system, including 64-bit. However, in practice, most of our development is done on Ubuntu 10 or 12.04 LTS systems, so these are best-supported.

Range Networks RAD1

Building for Range equipment is easiest, as it has no external dependencies. Just run the following commands:

cd openbts/trunk
autoreconf -i
./configure
make

With the build resolved, you'll need to build and link the transceiver appropriate for your hardware. For a Range Networks basestation unit these links are

(from OpenBTS root)
cd apps
make
ln -s ../TranceiverRAD1/transceiver .
ln -s ../TranceiverRAD1/ezusb.ihx .
ln -s ../TranceiverRAD1/fpga.rbf .

Ettus UHD Radios (B100, N210, USRP2...)

For all modern Ettus hardware (USRP2, B100, N200 and E100 series) you use the UHD (universal hardware device) libraries. Instructions to install these libraries can be found  here. USRP2 and N200 series also require host-based resampling support (though it doesn't hurt the B100 either):

cd openbts/trunk
autoreconf -i
./configure --with-uhd --with-resamp
make

Additional built time options for UHD devices include 10 MHz external reference support. For example, to use the front panel reference input on a N210, configure with the following options:

cd openbts/trunk
autoreconf -i
./configure --with-uhd --with-resamp --with-extref
make

With the build resolved, you'll need to build and link the transceiver appropriate for your hardware. For the UHD installs:

#(from OpenBTS root)
cd apps
ln -s ../Transceiver52M/transceiver .

Ettus USRP1

The USRP1 has been deprecated by Ettus, making this install more difficult. To run OpenBTS using the USRP1, you'll need to install GNU Radio. If you ordered an older USRP-based Range Developers' Kit, GNU Radio is already installed. For more information on installing GNU Radio go  here. Make sure to install something after 3.3.0, but before 3.5.0 (where they removed USRP1 support). With that installed:

Standard two daughterboard configuration (Tx side A, Rx side B):

cd openbts/trunk
autoreconf -i
./configure --with-usrp1
make

Single daughterboard configuration (Tx and Rx on side A). Side B is unused.

cd openbts/trunk
autoreconf -i
./configure --with-usrp1 --with-singledb
make

With the build resolved, you'll need to build and link the transceiver appropriate for your hardware. For the USRP1 installs:

#(from OpenBTS root)
cd apps
ln -s ../Transceiver52M/transceiver .

#and for the USRP1, install std_inband.rbf
sudo mkdir -p /usr/local/share/usrp/rev4/
sudo cp ../Transceiver52M/std_inband.rbf /usr/local/share/usrp/rev4/

Fairwaves UmTRX

Fairwaves UmTRX hardware use UHD, an modified version of UHD. Download it from  Fairwaves github and build just usual UHD - see  UHD wiki.

cd openbts/trunk
autoreconf -i
./configure --with-uhd
make

With the build resolved, you'll need to build and link the transceiver appropriate for your hardware. For the Fairwaves UHD installs:

#(from OpenBTS root)
cd apps
ln -s ../Transceiver52M/transceiver .

Configuring OpenBTS

With OpenBTS built, you now need to configure it to run correctly. There are a two key files that must be created for this to happen.

/etc/OpenBTS/OpenBTS.db

OpenBTS.db is the database store for all OpenBTS configuration. It must be installed at /etc/OpenBTS, which likely does not exist. So, to create this file:

(from the OpenBTS directory)
sudo mkdir /etc/OpenBTS
sudo sqlite3 -init ./apps/OpenBTS.example.sql /etc/OpenBTS/OpenBTS.db ".quit"

Test this by running:

sqlite3 /etc/OpenBTS/OpenBTS.db .dump

If you see a lot of configuration variables, the DB has been installed correctly.

Running OpenBTS

At this point, we should be able to perform a basic sanity check of OpenBTS.

(from OpenBTS root)
cd apps
sudo ./OpenBTS

You should see output like this:

OpenBTS>

And if you scan for GSM towers on your phone, you should see a 00101 (test) network. If you try to attach, it will reject you. This is because OpenBTS, by default, only allows registered handsets to connect. As we are not running our registration server (sipauthserve) no phones will camp. From here, we should look at a few OpenBTS configuration variables. Connect to OpenBTS with the OpenBTSCLI command:

(from OpenBTS root)
cd apps
sudo ./OpenBTSCLI

and then, in the CLI

config

You will see a lot of stock configuration options. You can find these listed here. Most of these only need to be tweaked if you are moving beyond a simple desktop setup. However, a few are required for basic operation. These are:

• GSM.Radio.Band - Set this to the GSM band appropriate for your hardware.
• GSM.Radio.C0 - This is the  ARFCN. Set it to something appropriate for your band.
• Control.LUR.OpenRegistration - Set this to a  regular expression matching the IMSIs of your test phones. This tells OpenBTS to not reject your handset just because your registration server (below) isn't responding. Useful for debugging and initializing the system.

The values can be modified from OpenBTSCLI with the config command. For example,

config Control.LUR.OpenRegistration .*

to allow registrations from any phone regardless of their provider. Caution: With this config all phones have access, without any restriction. When an antenna is attached, at least your neighbors will connect, so do not try this at home :-)

If these steps are complete, you have a working BTS. If they do not, check out the common errors.

You also need a home location registrar (sipauthserve), short message service center (smqueue) and switch (PBX) in order to register, send and receive sms, and send and receive calls. Those steps are below.

Build and Install the Subscriber Registry and Sipauthserve

OpenBTS depends on the installation of Sipauthserver the SIP authorization server for registration traffic. You will not be able to have a usable system without it.

Subscriber Registry

To setup the Subscriber Registry database run:

(from svn root)
cd subscriberRegistry/trunk/configFiles/
sudo mkdir -p /var/lib/asterisk/sqlite3dir
sudo sqlite3 -init subscriberRegistryInit.sql /var/lib/asterisk/sqlite3dir/sqlite3.db ".quit"
sudo mkdir /var/run/OpenBTS

Sipauthserve

Sipauthserve is an aptly-named daemon providing SIP authentication services. The SIP.Proxy.Registration config variable in openbts should point to its hostname and port.To build Sipauthserve, you MUST HAVE ALREADY BUILT OPENBTS. This is a makefile hack, and will hopefully be fixed at some point in the future.

To build Sipauthserve:

(from svn root)
cd subscriberRegistry/trunk
make

This will produce a sipauthserve executable.

As with OpenBTS, you'll need to configure sipauthserve. We assume /etc/OpenBTS/ already exists.

(from subscriberRegistry root)
sudo sqlite3 -init sipauthserve.example.sql /etc/OpenBTS/sipauthserve.db ".quit"

Running sipauthserve

Running sipauthserve will provide you with a registration server. To do so:

(from subscriberRegistry root)
sudo ./sipauthserve

sipauthserve does not have a CLI, so you'll only see a small output:

ALERT 139639310980928 sipauthserve.cpp:214:main: ./sipauthserve (re)starting

Remember, if you change any of the config variables, you'll need to restart sipauthserve for the changes to take effect.

Build and Install Smqueue

Smqueue is the store-and-forward message service packaged with OpenBTS. Building and running is very similar to the process used for OpenBTS.

Building Smqueue

In the smqueue/trunk directory, run the following commands:

autoreconf -i
./configure
make

You should now have an smqueue executable in the smqueue/trunk/smqueue directory.

Configuring Smqueue

Similar to OpenBTS, Smqueue also depends on a configuration file, located at /etc/OpenBTS/smqueue.db. Smqueue creates an empty, nonfunctional version of this db if it is not available. That's of no use. Instead, do as we did with OpenBTS and run the following command:

(from the smqueue directory)
sudo sqlite3 -init smqueue/smqueue.example.sql /etc/OpenBTS/smqueue.db ".quit"

That will initialize /etc/OpenBTS/smqueue.db with default values. These configuration variables should work without modification, and are listed here.

Running Smqueue

Smqueue is run with the following command:

(from the smqueue directory)
cd smqueue
sudo ./smqueue

Smqueue does not have a command-line interface, instead just reading configuration values and processing messages. So you'll only see a small output:

ALERT 140545832068928 smqueue.cpp:2421:main: smqueue (re)starting
smqueue logs to syslogd facility LOCAL7, so there's not much to see here

Remember, if you change any of the variables, you'll need to restart smqueue for the changes to take effect.

Selecting and Configuring a PBX

There are three primary open-source PBX/Soft switches available. These are  Asterisk,  FreeSwitch and  yate. The differences, tradeoffs, and advantages to using one system over the other are too numerous and outside the scope of this document. However, the key point is that all are actively supported and used by the OpenBTS community.

Asterisk is the "standard" OpenBTS PBX and is shipped in the commercial units. It's the easiest to set up, and most documented option. However, it's probably the most difficult. The steps for installing and configuring Asterisk to work with OpenBTS are located here.

FreeSwitch is an up-and-coming Asterisk competitor. Its interoperation with OpenBTS is supported primarily by the group at Berkeley. It provides programmatic voice and text routing, as well as a more flexible programming environment for voice/sms applications at the cost of being buggier and having less support. The steps for installing and configuring FreeSwitch to work with OpenBTS are documented here.

Yate is another SIP switch in active development. Instructions for interoperating with Yate are here. This is also supported by Berkeley and is buggy with less support than Asterisk.

RRLP Server

RRLP is a bit of a mess. As such, we generally don't think you should build it. However, if you're really interested in getting the location of your users, head over here.

Build and Install the CGIs

Running It All

Use one of the startup scripts or run each individual executable in a separate terminal/window. These would be:

smqueue/trunk/smqueue/smqueue
subscriberRegistry/trunk/sipauthserve
openbts/trunk/apps/OpenBTS
openbts/trunk/apps/OpenBTSCLI

Then turn on a phone with a GSM SIM card installed. It would be best if this SIM was NOT from a local carrier; then the phone will not immediately camp to one of their towers in the area. In most cases, on most phones, there is a way to select the specific network you wish to attach to. For this basic install, the network will be announced as: 001 01. Connect to that network. Your BTS should reply, allowing the phone to associate. If this fails, make sure you set the Control.LUR.OpenRegistration variable in OpenBTS.db.

With these two tests passed, you can now test the voice connection. Call 600 from the phone (9196 with FreeSWITCH) to call the "echo" service. If that's working, congrats!

Lastly, we can test SMS support. Send an SMS to 101 with a 7-10 digit number (configurable in smqueue). That is now your new number in the system. Do this with a second phone/SIM and then text between them. If this is working, congrats, your SMS services are working as well!

Debugging OpenBTS

By default OpenBTS logs to syslogd. As such, you can see all openbts traffic with the following command:

tail -f /var/log/syslog | grep OpenBTS

If you're seeing problems, check here for any glaring issues (Probably ALARM/ERR). You can similarly look for issues with sipauthserve and smqueue.

Updating OpenBTS

Please see UpdateOpenBTS.

---

OpenBTS is a registered trademark of Range Networks, Inc.