Cellular Network Infrastructure » Radio Access Network » OsmoTRX

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h1. LimeSDR

The "LimeSDR":https://myriadrf.org/projects/limesdr/ is a low-cost SDR board featuring the Lime Microsystems LMS7002 RF chip.

Key characteristics include:

* RF Transceiver: Lime Microsystems LMS7002M MIMO FPRF

* FPGA: Altera Cyclone IV EP4CE40F23 – also compatible with EP4CE30F23

M* emory: 256 MBytes DDR2 SDRAM

* USB 3.0 controller: Cypress USB 3.0 CYUSB3014-BZXC

* Oscillator: Rakon RPT7050A @ 30.72MHz

* Continuous frequency range: 100 kHz – 3.8 GHz

* Bandwidth: 61.44 MHz

* RF connection: 10 U.FL connectors (6 RX, 4 TX)

* Power Output (CW): up to 10 dBm

* Multiplexing: 2×2 MIMO

* Power: micro USB connector or optional external power supply

* Status indicators: programmable LEDs

* Dimensions: 100 mm x 60 mm

h2. RF Output Power

TBD

h2. Clock

The on-board clock is a 250ppb VCTCXO.  GSM strictly requires 30ppb, but 250ppb _should_  be sufficient for laboratory use.

h3. Clock Calibration

TBD

h3. Using external clock reference

TBD

h2. OsmoTRX on LimeSDR

In terms of OsmoTRX support, you will a relatively complex driver stack consisting of:

* "LimeSuite":https://github.com/myriadrf/LimeSuite.git containing the actual drivers and utilities for LimeSDR

* "SoapySDR":https://github.com/pothosware/SoapySDR.git as middleware that wraps LimeSuite

* "SoapyUHD":https://github.com/pothosware/SoapyUHD.git as plug-in exposing SoapySDR devices to UHD

* UHD as the driver interface below OsmoTRX

You will need to observe the following dependencies when building the above:

# SoapyUHD depends on SoapySDR

# LimeSuite depends on SoapySDR.

h3. Verifying the driver stack

You can ensure that LimeSuite recognizes your device using the *LimeUtil* part of LimeSuite:

<pre>

$ LimeUtil --find                109/0/0

  * [LimeSDR-USB, media=USB 3.0, module=STREAM, addr=1d50:6108, serial=0009060B00xxyyzz]

</pre>

You can ensure that SoapySDR and LimeSuite work together as expected using the *SoapySDRUtil* part of SoapySDR:

<pre>

$ ./SoapySDRUtil --find                  101/0/0

######################################################

## Soapy SDR -- the SDR abstraction library

######################################################

linux; GNU C++ version 6.3.0 20170221; Boost_106200; UHD_003.009.005-0-unknown

Found device 0

  addr = 1d50:6108

  driver = lime

  label = LimeSDR-USB [USB 3.0] 9060B00462B1C

  media = USB 3.0

  module = STREAM

  name = LimeSDR-USB

  serial = 0009060B00xxyyzz

</pre>