[USRP-users] How to implement multi_usrp (with MIMO)?

Furkan Elibol

Hi,

I tried the same code with stream command for future as the rx_timed_samples.cpp. but the result is same, I still can not receive any packet.

I think my problem is related with subdevice mapping. Because when I try the same multi usrp library and same code with only setting one usrp2, it can receive packets as expected.

And I wonder is there any test program for multi usrp setup.

Goto Highmesh to know more.

Thanks...

Furkan

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From: Josh Blum <***@ettus.com>;

To: ;

Subject: Re: [USRP-users] How to implement multi_usrp (with MIMO)?

Sent: Tue, Jan 4, 6:28:23 PM

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My first guess is that you need to issue a stream command for a time in

the _future_. If you issue a command to stream _immediately_, the packet

streams from the individual devices will not align. If the packets do

not align, they are dropped inside the uhd.

-josh

Take a look at this fun

On 01/04/ 05:16 AM, Furkan Elibol wrote:

Hi,



I try to collect sync data from 2 usrp2s with mimo cable which uhd supports. I

modified rx_samples_to_file.cpp. I can compile the new c++ code without error

but when i run the code i can not receive any packet. I need help about this

problem. Please check my code and inform me if there are any mistake. I attached

the whole code and output of the code are below;



linux; GNU C++ version 4.4.3; Boost_; UHD_..1



Warning:

    error in pthread_setschedparam

    Failed to set thread priority 0.5 (realtime):

    Performance may be negatively affected.

    See the general application notes.



Creating the usrp device with: ...

Current recv sock buff size: bytes

Current recv sock buff size: bytes



Warning:

    error in pthread_setschedparam

    Failed to set thread priority 0.5 (realtime):

    Performance may be negatively affected.

    See the general application notes.



Warning:

    error in pthread_setschedparam

    Failed to set thread priority 0.5 (realtime):

    Performance may be negatively affected.

    See the general application notes.

   

Using Device: Multi USRP:

  Device: USRP2/N Series multi-device

  Mboard 0: USRP2-REV4 mboard

  Mboard 1: USRP2-REV4 mboard

  RX DSP 0: USRP2-REV4 ddc0

  RX Channel: 0

    RX Dboard: USRP2-REV4 dboard (rx unit)

    RX Subdev: WBX (0x)

  RX DSP 1: USRP2-REV4 ddc0

  RX Channel: 1

    RX Dboard: USRP2-REV4 dboard (rx unit)

    RX Subdev: WBX (0x)

  TX DSP 0: USRP2-REV4 duc0

  TX Channel: 0

    TX Dboard: USRP2-REV4 dboard (tx unit)

    TX Subdev: WBX (0x)

  TX DSP 1: USRP2-REV4 duc0

  TX Channel: 1

    TX Dboard: USRP2-REV4 dboard (tx unit)

    TX Subdev: WBX (0x)



Time sync: 1



sdev spec 0: Subdevice Specification:

    Channel 0: Daughterboard 0, Subdevice



sdev spec 1: Subdevice Specification:

    Channel 0: Daughterboard 0, Subdevice



Setting RX Rate: 5. Msps...

Actual RX Rate: 5. Msps...



Setting RX Freq: 120. Mhz...

Actual RX Freq: 120. Mhz...

Actual RX Freq: 120. Mhz...



Setting RX Gain: 15. dB...

Actual RX Gain: 15. dB...

Actual RX Gain: 15. dB...



LO Locked = 1

LO Locked = 1

OO

stream num samps:

stream flag: 1



OOnum acc samples=0

num rx samples= 0

max recv samp per packet: 362

buff size: 362



num acc samples=0

num rx samples= 0

max recv samp per packet: 362

buff size: 362



num acc samples=0

num rx samples= 0

max recv samp per packet: 362

.

.

.



As seen above i can not receive any packet. I use wbx as db. I can collect data

from single usrp2+wbx with original rx_samples_to_file.cpp.

Any discussion???



furkan







this is the print for mboard0



sdev spec 0: Subdevice Specification:

    Channel 0: Daughterboard 0, Subdevice





this is the print for mboard1



sdev spec 1: Subdevice Specification:

    Channel 0: Daughterboard 0, Subdevice

 



So, everything should be fine.

I guess the prints could be more clear.

-Josh







     







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Laurie Young Currently attempting to implement this myself using the next UHD branch
(UHD_..). Furkan, I think you need to set up the
MIMO master and slave using the "mimo_mode" arg, ie:
dev_addr["addr0"] = "192.168.10.2";
dev_addr["addr1"] = "192.168.20.2";
dev_addr["mimo_mode0"] = "master";
dev_addr["mimo_mode1"] = "slave";

Then to issue the stream command in the future do (I think):
stream_cmd.stream_now = false;
stream_cmd.time_spec = mdev->get_time_now() + 1.0;
mdev->issue_stream_cmd(stream_cmd);

However I get stuck here. I'd like to RX from both the master and slave
channels but doesn't recv() just stream from a uhd::device? So if you set up
a multi_usrp::sptr called mdev and do uhd::device::sptr dev =
mdev->get_device() how can I specify to recv() from the master/slave?

Laurie