Hi Stephane,
I'm back from MWC, catching up with the mailing list.
On Sun, Feb 24, 2013 at 12:22 AM, stephane@shimaore.net 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: http://blog.shimaore.net/2013/02/umtrx.html 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 welcome.
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!
-- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru