Hi all, I have tried to send packets to the receiver from /digital/narrowband folder and it has mostly succeeded. The output I was able to get when I sent the following commands were
Sender: ./benchmark_tx.py -p 4 -M 2 -f 2.435000061G --tx-gain=28 -r 250000 Receiver: ./benchmark_rx.py -p 4 -f 2.435000061G --rx-gain=54 -r 250000 ok = True pktno = 1323 n_rcvd = 1303 n_right = 1294 ok = True pktno = 1324 n_rcvd = 1304 n_right = 1295 ok = True pktno = 1325 n_rcvd = 1305 n_right = 1296 ok = True pktno = 1326 n_rcvd = 1306 n_right = 1297 ok = True pktno = 1327 n_rcvd = 1307 n_right = 1298 ok = True pktno = 1328 n_rcvd = 1308 n_right = 1299 ok = True pktno = 1329 n_rcvd = 1309 n_right = 1300 ok = True pktno = 1330 n_rcvd = 1310 n_right = 1301 ok = False pktno = 1331 n_rcvd = 1311 n_right = 1301 But there were a few packets where I have not received them correctly. I guess only 95% of them were efficient in transmitting. I have tried changing the gain settings and what I observed was that if I decrease the gain from its normal value, the reception of packets are somewhat less efficient. Can I kindly know what I might be able to do in order to receive those packets in a more efficient way or is that what generally happens in a real world transmission? Thanks Regards, Dave On Tue, Sep 22, 2015 at 1:02 PM, Marcus Müller <marcus.muel...@ettus.com> wrote: > Ok, > > This is because I have changed my folder to /digital/ofdm, I have started > to receive packets. > > this means that you're using something *completely* different than before. > It's simply a completely different transceiver system. > > kindly advise if I need to figure out the combination settings till most > of them receive properly? > > Yes. You will need to figure out the optimum settings. Increase gain on > the RX end, see if things get better or worse. Find an optimum for that. Do > the same with the TX gain. > > Because even though I did not set any sample rate, the transmitter sent > the information. > > As mentioned before multiple times: run the programs with "--help". They > will show you what default settings they have. > > Please help. Please excuse me if I am being naive in asking these. > > It's alright to ask questions, but please remember to apply the things we > tell you. > > Best regards, > Marucs > > > On 22.09.2015 00:59, Rama V wrote: > > Hi, > As advised, the problem has been solved to a little extent where I have > got the below results by giving the commands as > > Sender : ./benchmark_tx.py -f 2.435G --tx-gain=25 > Receiver: ./benchmark_rx.py -f 2.435G --rx-gain 50 > > ok: True pktno: 1971 n_rcvd: 1687 n_right: 358 > ok: False pktno: 1972 n_rcvd: 1688 n_right: 358 > ok: False pktno: 1973 n_rcvd: 1689 n_right: 358 > ok: False pktno: 1974 n_rcvd: 1690 n_right: 358 > ok: True pktno: 1975 n_rcvd: 1691 n_right: 359 > ok: False pktno: 1976 n_rcvd: 1692 n_right: 359 > ok: True pktno: 1977 n_rcvd: 1693 n_right: 360 > ok: False pktno: 1978 n_rcvd: 1694 n_right: 360 > ok: True pktno: 1979 n_rcvd: 1695 n_right: 361 > ok: True pktno: 1980 n_rcvd: 1696 n_right: 362 > ok: False pktno: 1981 n_rcvd: 1697 n_right: 362 > ok: True pktno: 1982 n_rcvd: 1698 n_right: 363 > ok: False pktno: 1983 n_rcvd: 1699 n_right: 363 > ok: True pktno: 1984 n_rcvd: 1700 n_right: 364 > ok: False pktno: 1985 n_rcvd: 1701 n_right: 364 > ok: True pktno: 1986 n_rcvd: 1702 n_right: 365 > ok: False pktno: 1987 n_rcvd: 1703 n_right: 365 > ok: True pktno: 1988 n_rcvd: 1704 n_right: 366 > > This is because I have changed my folder to /digital/ofdm, I have started > to receive packets. But I guess this is only 50% efficient in receiving > packets. Not all of them have been receiving properly. kindly advise if I > need to figure out the combination settings till most of them receive > properly? Because even though I did not set any sample rate, the > transmitter sent the information. Please help. Please excuse me if I am > being naive in asking these. > > Regards, > Dave > > On Mon, Sep 21, 2015 at 11:00 AM, Rama V <ramav...@gmail.com> wrote: > >> Hi, >> Thanks Marcus. I will do as you have advised and approach if any >> uncertainties. >> >> Regards, >> Dave >> >> On Mon, Sep 21, 2015 at 10:16 AM, Marcus Müller < >> <marcus.muel...@ettus.com>marcus.muel...@ettus.com> wrote: >> >>> Hi Dave, >>> >>> you shouldn't be modifying the python files before you understand what >>> they do exactly. Please revert your edits, because it will be impossible to >>> help you if you don't use the same scripts as we do, obviously. We've >>> talked about this[1]. >>> >>> So: >>> >>> Sender : benchmark_tx.py -f 2.435G -r 250k >>> Receiver : benchmark_rx.py -f 2.435G >>> >>> That's wrong! Now, your transmitter sends 250,000 bits per second, but >>> your receiver expects 100.000 (the default value, which doesn't work with >>> your hardware), so that's not good. Use the same setting for both >>> benchmark_tx and benchmark_rx. >>> >>> So all you say is I need to change and play with the sampling rates and >>> --tx-amplitude until the received packet becomes 'n_rcvd=1' >>> >>> No. RF is not "hey, there's this correct setting, let's apply it >>> everywhere"; you'll have to figure out which combination settings work >>> best. Generally, I'd leave the --tx-amplitude untouched, because 0.25 is a >>> sane value for the digital samples; what you want is analog gain, not >>> digital scaling. >>> >>> You should really set a TX gain and a RX gain. Try around with a few >>> different gain settings for RX and TX gain -- a good approach would be to >>> set something like 25 dB TX gain, and around 50 dB RX gain, if you place >>> your TX and RX antennas far enough from each other. Notice that I'm >>> assuming you're using antennas, and no direct connection! If you're using a >>> direct cable between TX and RX, please use an attenuator, because you might >>> otherwise damage your hardware. >>> >>> To find out how to change the gains, please read the output of >>> benchmark_tx.py --help >>> and of >>> benchmark_rx.py --help >>> >>> >>> Best regards, >>> Marcus >>> >>> >>> [1] >>> http://lists.gnu.org/archive/html/discuss-gnuradio/2015-09/msg00124.html >>> >>> On 21.09.2015 16:48, Rama V wrote: >>> >>> I have tried the following commands in the terminal >>> >>> Sender : benchmark_tx.py -f 2.435G -r 250k >>> Receiver : benchmark_rx.py -f 2.435G >>> >>> But the data packets are not being sent correctly. I have been receiving >>> the packets as ok=false. I have tried modifying benchmark python scripts. >>> Can I do the modification of those scripts or evrything needs to be given >>> in the command line. Please excuse me as I am slightly unable to >>> understand. Thanks >>> >>> Regards, >>> Dave >>> On Sep 18, 2015 2:21 PM, "Rama V" < <ramav...@gmail.com> >>> ramav...@gmail.com> wrote: >>> >>>> Thanks for the reply Michael. I will look into that as you have >>>> advised. So all you say is I need to change and play with the sampling >>>> rates and --tx-amplitude until the received packet becomes 'n_rcvd=1' and >>>> CRC check changes to 'ok=true' from the narrowband folder? >>>> >>>> Regards, >>>> Dave >>>> >>>> On Fri, Sep 18, 2015 at 12:40 PM, Michael Dickens < >>>> <michael.dick...@ettus.com>michael.dick...@ettus.com> wrote: >>>> >>>>> Hi Dave - I'm thinking that you are confusing "--samples-per-symbol" >>>>> for the sample rate. I think the option you're looking for is "-r". Look >>>>> at >>>>> the "--help" for those examples when you get a chance. - MLD >>>>> >>>>> On Thu, Sep 17, 2015, at 02:01 PM, Rama V wrote: >>>>> >>>>> Thank you very much Michael. I will follow up on your advice. I am >>>>> sorry that I wasn't able to understand some parts in GNU RADIO and didn't >>>>> specify enough information. Regarding the question, I have been doing the >>>>> benchmark in the digital/ narrowband/ folder. The exact commands I have >>>>> been working on are >>>>> >>>>> Sender: benchmark_tx.py -f 2.435G --tx-gain 25 --samples-per-symbol >>>>> 250000 >>>>> >>>>> Receiver: benchmark_rx.py -f 2.435G >>>>> >>>>> When I give 250kS/s, my laptop freezes. USRP is XCVR2450. So I started >>>>> to give less Samples like 50kS/s so that they communicate with each other >>>>> without errors. But I couldn't figure out the solution to that. So I just >>>>> have a doubt whether I need to modify benchmark scripts or is it enough >>>>> for >>>>> the parameters I give in the command line. Thanks for the help. Please >>>>> advice >>>>> >>>>> >>>>> >>>> >>>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing >>> listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> Discuss-gnuradio@gnu.org >>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >> > >
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