Re: [Discuss-gnuradio] UHD Error of No Control Response

[Bojun Sun]

Hi Marcus,

Thanks for the advice. I tried another laptop with GB Ethernet and it can successfully receive the corresponding constellation map. However, there are still have some problem.

• For TX, the LED A on USRP still have the similar status like before, that is, blink with dim light. I googled NI USRP 2920 docs and Ettus N210 docs, both of them don't have this status. My questions are:

1. Is there any potential problem(s) according to the LED status?
2. If I burn USRP N210 FPGA&fw images in NI USRP 2920, which product docs should I refer to?
3. Sometimes when I run the TX code, I still get the underflow stdout "U" and sometimes it disappear. Is it because of the HW resource of my laptop?
   

• For the RX, I can receive the corresponding constellation map. However, sometimes when I stop the program, it popup a return code of -9 and sometimes it shows overflow stdout "D".
  

• For both TX and RX running at the same time, it shows stdout "X"s like the following info:

​

• When I stop running both TX and RX codes, my GNU Radio usually stuck. Is it also the limitation of my laptop HW resource?

Thanks and regards,

Bojun

On Tue, Nov 8, 2016 at 3:25 AM, Marcus Müller <address@hidden> wrote:

Well, harsh truth: get another laptop. Even if you can get the Gigabit Ethernet frame format, your laptop's network card limits your data rate to 100 Mb/s, which is simply far far far too little to contain the samples you'd need for recreating IEEE802.11 signals; a complex sample for / from the USRP has 4B, and thus, 100Mb/s limits your *cumulative* sampling rate and thus bandwidth to about 3 MHz.

Best regards,

Marcus

On 08.11.2016 01:14, Bojun Sun wrote:

Hi Marcus,

Thanks for the quick reply. Unfortunately, my laptop doesn't has GB Ethernet card. Therefore, the NI support people told me that I can use a GB switch as a converter to make them communicate. My switch can support 10/100/1000 Ethernet.

Best regards,

Bojun

On Mon, Nov 7, 2016 at 6:57 PM, Marcus Müller <address@hidden> wrote:

Hi Bojun,

this looks like packets don't reach their destination.
Can you make sure that both your switch as well as your network card are really Gigabit, and not just fast (100Mb/s) Ethernet?

Best regards,
Marcus

On 08.11.2016 00:49, Bojun Sun wrote:

Hi all,

I've been experiencing a kind of UHD error of no control response and have no clue of the cause. Can you guys help me figure it out? Thanks☺

My goal and HW connection:
For the first stem, I want to run this code (https://github.com/bastibl/gr-ieee802-11) using USRP 2920s. The connection is: USRP1 connect to USRP2 by MIMO cable; USRP2 connect to GB switch by Ethernet cable; and laptop connect to GB switch by another Ethernet cable.

My questions:

• When I run the TX code, the LED A of USRP 2920 blink with dim light. I also wire the TX1/RX1 port to an oscilloscope, I can observe the signal frequency at the desired frequency. From the GNU Radio debugging window, it shows the following information. Is it working properly? I'm not sure because the status of LED A is blink.

• When I run the RX code, I can't observe the correct constellation map and get UHD error in the debugging window. The error messages are as follows:

after seconds, get the following error. If I stop the program, it will end up with a return code -9. I googled the meaning of return code and didn't find the meaning.

I run the code for another time, it popup similar error messages.

​

Some answers of previous questions in the archive of GNU Radio mailing list says it might be the ARP problem. I added the IP and MAC addresses into the ARP table but it didn't solve this problem.

• I googled some solution of this "no control response" questions and found on http://files.ettus.com/manual/page_general.html#general_ounotes

but I'm not sure whether it is the reason that I got the error message. What's more, if so, I'm still confused that the buffer refers to, the buffer of USRP or the buffer of my laptop? and how to solve it?

My system info:

• HW: two NI USRP 2920s, one NetGear GB switch
• Software: GNU Radio 3.7.10.1, UHD 3.11
• OS: Ubuntu 16.04
• When run uhd_find_devices:

• When run uhd_usrp_probe --args "addr=192.168.10.2":

• When run uhd_usrp_probe --args "addr=192.168.10.3":

​

Best regards,

Bojun Sun

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