transceiver won't start; fpga build error

Alexander Chemeris alexander.chemeris at
Tue Mar 5 13:32:53 UTC 2013

Hi Stephane,

I'm back from MWC, catching up with the mailing list.

On Sun, Feb 24, 2013 at 12:22 AM,  <stephane at> wrote:
>> I'll go ahead and recompile openBTS using your version. Thank you!
> That worked out rather smoothly. I can see the '00101' GSM network on my
> phone and OpenBTS attempts to SIP REGISTER when I choose it on the
> phone.
> Here are my notes, I'll be posting further updates there as well:
> Hope this helps.

Nice stuff!

Though I should note that FPGA and ZPU compilation and flashing is not
needed in most cases. UmTRX comes pre-flashed and should not need all
those cumbersome steps.

> Next steps for me are to setup FreeSwitch (and maybe OpenSIPS) so that I
> can start testing calls.

Thank you for your patch to make it working with OpenSIPS :) Looking
forward for more contributions to the SIP side of things. They're need
quite some attention, as you already noticed.

One idea is to have a normal state machines for SIP, independent from
GSM state machines. Current tightly coupled integration between SIP
and GSM states makes both sides to break in various cases. I even
thought about completely replacing oSIP with a library which already
implements SIP state machines, like Sofia-SIP. But this requires
research on whether we'll be able to implement things which require
non-standard behavior, like handover. Thoughts on this topic are

> Question: I used RX1 and TX1 on the board to connect the antennae, but
> `transceiver` says "using transmit antenna RX1" and "using receive antenna
> TX2", does that mean I should use RX1/TX2 instead, or is this a
> configuration parameter I should modify in OpenBTS.db?

Sorry for the confusion. TX1/RX1 label on the board refer to RX/TX of
the channel 1. While in the software channel 1 is referred to as
"daughter board A" and RX1 means we use LNA1 input on LMS chip.

In other words, there are two LMS chips on UmTRX:
channel 1 (daughter board A) - RX1, TX1, SCN1 labels on a PCB
channel 2 (daughter board B) - RX2, TX2, SCN2 labels on a PCB

And each LMS chip has RX1, RX2, RX3 inputs and TX1, TX2 outputs
("antennas" in software) with the following mapping:
RX1 (software) = RXn (PCB label)
RX2 (software) = not connected on the PCB
RX3 (software) = SCNn (PCB label)
TX1 (software) = not connected on the PCB
TX2 (software) = TXn (PCB label)

> PS: Congratulations to everyone involved in making this so painless!
> Eight hours (lunch included) from unpacking to being able to see the MNC
> show up on a phone is _very_ nice.

Thank you!

Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио

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