UmTRX integration with OpenBTS

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Alexander Chemeris alexander.chemeris at gmail.com
Wed Jun 20 04:11:05 UTC 2012


On Wed, Jun 20, 2012 at 5:33 AM, Thomas Tsou <thomastsou at gmail.com> wrote:
> On Mon, Jun 18, 2012 at 1:31 AM, Alexander Chemeris
> <alexander.chemeris at gmail.com> wrote:
>> Nothing really tested yet. At least you should do this steps:
>> ./umtrx_lms.py --lms 1 --lms-rx-enable 1
>> ./umtrx_lms.py --lms 1 --lms-rx-pll-tune 925e6
>> ./umtrx_lms.py --lms 1 --pll-ref-clock 26e6 --lpf-bandwidth-code 0x0f
>> --lms-auto-calibration
>>
>> Then you need to select Rx input with register 0x75. Should be
>> something like this:
>> ./umtrx_lms.py --lms 1 --reg 0x75 --data 0xF0
>>
>> There are a lot of other settings for Rx fontend in LMS which I don't
>> understand, but I guess defaults should be fine for the start. Then we
>> could tune them with Andrey's help.
>>
>> If signal is too low you may need to tune Rx VGA2 gain with the
>> register 0x65 (refer to the programming guide for the register values
>> encoding).
>
> Connected a call - all seven actually. It's quite stable once setup.

Good job!

How did you setup Rx on LMS?
And anything else to know before testing?

> 'fairwaves/umtrx' branch with u2plus_umtrx-20120424.bit and following
> patch.

Now it's time to make this a configure option. :)

> I and Q were swapped.

So I/Q order is different at Rx and Tx?We could fix this in FPGA.

With the multi-ARFCN support, do you think it will be hard to add
support for the second channel in UmTRX to OpenBTS to get 15 calls?
Second channel is not fully supported by UmTRX FPGA firmware yet, but
we should do this soon.

-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru



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