20 Jun
2012
20 Jun
'12
11:23 p.m.
On Wed, Jun 20, 2012 at 12:11 AM, Alexander Chemeris
<alexander.chemeris(a)gmail.com> wrote:
UmTRX could be detected at runtime. There are already device checks
for USRP1 and B100.
The OpenBTS side should be straightforward. The multicarrier
implementation accepts independent transceiver inputs with the
channelization acting as multiplexer. With separate physical channels,
we just remove the channelization and pass transceiver connections
straight through to the device interface.
I added the second Tx channel in UHD some time ago, but never created
a test case.
Thomas
On Wed, Jun 20, 2012 at 5:33 AM, Thomas Tsou
<thomastsou(a)gmail.com> wrote:
I used some combination of the above Rx settings and the previous Tx
sequence. I don't recall the exact order, but I didn't use any
commands or arguments that haven't been mentioned. I didn't change the
VGA2 setting and for much of the testing had a 3dB attenuator on the
LNA input (probably didn't matter).
Remember to set the ARFCN to match the tuning frequencies. I did not
and spent some time trying to figure out why only RACH bursts were
decoded.
On Mon, Jun 18, 2012 at 1:31 AM, Alexander
Chemeris
<alexander.chemeris(a)gmail.com> wrote:
Good job!
How did you setup Rx on LMS?
And anything else to know before testing? 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.
'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.