Cellular Network Infrastructure » Radio Access Network » OsmoTRX

h1. Fairwaves UmTRX and UmSITE

"Fairwaves UmSITE":https://fairwaves.co/products/equipment/ is a fully fledged GSM BTS which runs Osmocom stack. 

"Fairwaves UmTRX":https://umtrx.org is an SDR used in Fairwaves UmSITE BTS. It can also be purchased separately and is frequently used by commercial companies and enthusiasts to run [[OsmoTRX]]. [[UmTRX]] was created at the early days of [[OsmoTRX]] (even predating the official @osmo-trx@) and evolved together with @osmo-trx@ providing excellent compatibility.

Following GSM recommendations UmTRX has a much more precise reference clock and built-in GPSDO function to keep the frequency accuracy within 50ppb required by the GSM standard. This resolves issues often faced by users of other SDRs where phones can't detect a network due to excessive frequency error.

h2. Installation

# Install UHD and an UmTRX UHD module as described in the "UmTRX documentation":https://umtrx.org/applications/driver/

# Install @osmo-trx@ as usual. If you're compiling from sources, just compile with default parameters.

h2. Running

A typical command line to run @osmo-trx@ with UmTRX:

<pre>

chrt 20 osmo-trx -c 2 -a "fifo_ctrl_window=0,status_port=12345"

</pre>

# @-c 2@ enables dual-TRX mode,

# @fifo_ctrl_window=0@ works around a frequent issue when UHD can't connect to a UmTRX on the first try.

# @status_port=12345@ enables a special JSON API which exports the whole UHD property tree to allow runtime fine tuning and status query by external applications. See "umtrx_property_tree.py":https://github.com/fairwaves/UHD-Fairwaves/blob/master/host/utils/umtrx_property_tree.py for an example library to access this API and "umtrx_query_sensors.py":https://github.com/fairwaves/UHD-Fairwaves/blob/master/host/utils/umtrx_query_sensors.py for an example use of this API to query UmTRX VSWR, voltage and temperature sensors while @osmo-trx@ is running.