GSM-Basestation

Setting Up a GSM Base Station

Quickly create a GSM network that can support calls and SMS. Previously covered on this RTL-SDR Post.

Requirements

Software

• [* UHD

• OpenBTS

Hardware

• Computer or Raspberry Pi running DragonOS](/radio/dragonos)

• Software Defined Radio (SDR)

  • Phone
  • SDR

Cemaxecuter Guide

Watch on YouTube.

Set Up Base Station Calling

Plug in the SDR.

• Connect SDR to the computer.
• Perform Checks.

lsusb
ifconfig

Configure the network connection for IPv4.

• Create a new interface netmask graphically or via CLI:

Interface#
IPV4
192.168.1.20/24

Confirm the setup using:

uhd_find_devices

Ensure the device is listed.

Update the configuration:

cd /usr/src/osmo-nitb-scripts
sudo nano config.json
sudo main_uhd.py -u --sip

• -u enables interactive mode.
• --sip enables Asterisk support.

Run the following in another terminal:

/usr/bin/osmo-trx-uhd -C /etc/osmocom/osmo-trx-uhd.cfg

Set Up Base Station OpenBTS

Plug in the SDR.

• Confirm the interface name:

lsusb
ifconfig

Configure the network connection for IPv4.

• Create a new interface netmask:

Interface#
IPV4
192.168.1.20/24

Navigate to the OpenBTS directory:

cd /usr/src/OpenBTS/

Register the SIM:

sudo /usr/src/OpenBTS/OpenBTS

Connection should be quick.

Details

Compatible Phones

For this to work, the mobile device needs to have a Calypso baseband chip.

Motorola:

• C115 $40 or C117 (E87)

• C123/C121/C118 (E88)

• C140 $27 or C139 $15 (E86)

• C155 (E99)

• V171 (E68/E69)

SonyEricsson:

• J100i $8.99

Compatible SDR

See the comparison table.

Requirements:

• Full-duplex SDR

• Covers frequency ranges: 850 MHz and 1900 MHz

• Compatible with the software

YateBTS works with:

• BladeRF $540+

srsRan supports:

• BladeRF $540+

• *#### Osmo-nitb works with:

• [LimeSDR*)(/limesdr-products)

• AntSDR E200