UmTRXv2 final project

Alexander Chemeris alexander.chemeris at
Tue Jul 3 20:18:19 UTC 2012

Hi Jean-Samuel,

On Tue, Jul 3, 2012 at 10:59 PM, Jean-Samuel Najnudel - BJT PARTNERS
SARL <jsn at> wrote:
> Hi Alexander,
> Thank you very much for your e-mail.
> 1/ They did not started the PCB manufacturing yet. They are still
> waiting for my feedback on the questions I asked to Andrey.
> Actually, if we need to replace the SRAM and/or the flash to use
> cheaper equivalent components, we may need to reroute the PCB. This is
> why I ask them to wait for the feedback from Andrey before starting
> the PCB production. They can start as soon as we let them know what we
> do about the SRAM and the flash (with or without PCB files update).
> Anyway, I was not very worried about the delay. As discussed together
> last time in Paris, before deploying the UmTRX on the field, we would
> need OpenBTS to support handover. Even for tests, if I open the
> network without handover, because of the terrain in Mayotte, there
> will be so much call drops nobody in Mayotte will accept to use our
> network anymore in the future. Really, handover is very important in
> Mayotte.
> As I understand OpenBTS is under development but it is quite hard
> work. It will probably not be ready before the end of this summer.
> This is why I did not feel very worried about the PCB production
> delay.

We really need to get prototypes ASAP for many reasons - we have to
start certification process, we still need to find enclosures, we have
other pilots pending, etc. And every week of delay is painful for us.

> Anyway, I will do my best to get the UmTRX prototypes ready as soon as
> possible. I just need a feedback from Andrey because, if it does not
> lower the UmTRX board performances, we should really try to find an
> alternative solution to use cheaper SRAM and flash chips. This could
> improve a lot the cost structure of the UmTRX.

We should be fine with this chip:
(with no PCB changes).

> 2/ I did not contacted Lime yet but I will do this as soon as
> possible. I will do my best to get the LMS chips on time.
> By the way, for both PCB assembly and LMS order, how many UmTRX board
> would you like the fab makes ? We discussed together about 5 or 10
> units but we did not took the final decision yet. It can be any
> reasonable number between 5 and 10. Please let me know the quantity
> you would need. I will ask the fab and order the component quantities
> we need.

We have only 5 FPGAs left, so I think we should assembly 5 prototypes.
I.e. we need 10 LMS chips.

But we could safely order more PCBs, because we're pretty sure PCB won't change.

> By the way, the meeting with the fab this morning was fine and they
> are ready to start the production asap.

Please, start PCB manufacturing ASAP.

Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио

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