I don't believe this problem can be solved by adjusting the loop bandwidth. Applying faster tracking algorithm may solve this problem, but I think it takes long time to develop for a new guy.
On Wed, Mar 6, 2013 at 3:44 AM, Jawad Seddar <jawad.sed...@gmail.com> wrote: > Hello, > > I am getting the same problem you described here i.e very high packet loss > in discontinuous mode (first and last packet received with ok=False). > > Could you please elaborate on how to adjust the synchronisation loops > bandwidth? > I have tried adjusting the --timing-bw and --phase-bw parameters on the > benchmark-rx example, but I don't know if that is what you were talking > about. > > > *From:* Adeel Anwar <address@hidden> >> *To:* Alex Zhang <address@hidden> >> *Cc:* address@hidden >> *Sent:* Monday, 4 March 2013 5:51 PM >> *Subject:* Re: [Discuss-gnuradio] Very low packet loss rate for the >> discontinuous BPSK communications- the analysis and looking for solution >> >> Alex, >> >> 1: U can try adjusting the synchronization loops bandwidth (Phase/Timing >> etc) see PFB_Timing documentation >> 2: Try reducing the receiver gain (for a constant tx-amplitude/gain) or >> reduce transmission amplitude/gain (for constant rx gain) >> >> -Adeel >> >> >> >> >> >> >> On Sat, Mar 2, 2013 at 10:21 AM, Alex Zhang <address@hidden> wrote: >> >> I think you may rarely get the correct packet with pktno = 0, in >> continuous mode, as my guess. Your received correct packet starts from >> pktno = 1. >> Could you also try the discontinuous mode for the BPSK communications? >> >> My question is actually a problem that how to implement a more reliable >> BPSK mod/demod in burst mode. The current bpsk example in GNURadio does not >> work well in burst mode. >> >> >> On Fri, Mar 1, 2013 at 11:12 PM, Manu T S <address@hidden> wrote: >> >> Alex, >> >> If it was about loosing sync, we would mostly loose the first packet even >> if we are sending in continuous mode. I personally face no such issues. >> >> >> On Sat, Mar 2, 2013 at 3:25 AM, Alex Zhang <address@hidden> wrote: >> >> Seems no one can shed a light on this topic? >> >> >> On Thu, Feb 28, 2013 at 10:25 PM, Alex Zhang <address@hidden> wrote: >> >> Hello, >> >> In the current gr-digital/narrowband, I am using the benchmark_tx.py and >> rx.py to test the bpsk communications. >> It is found that the packet loss rate is very high (70% loss) in >> discontinuous mode where every 5 packets are in a burst. But in continuous >> mode, the paket loss rate is less than 10% for the same point to point >> link. >> >> I captured the waveform data. From the observed result, it seems that for >> each burst (5 packet), the bpsk receiver needs to re-do the frequency/time >> sync. This will directly causes that the first packet of each burst will >> definitely be crashed. Also, some burst can not be demodulated correctly at >> all. For the same reason, even in the continuous mode, the very first >> packet is also crashed at the receiver. >> >> I have tried to add very long preamble for each packet to ensure the >> data part of the packet can be received in well sync status. But the result >> is not very good. >> >> Before I get further investigation on the solutions, just wondering if >> any ideas or existing work within this community. >> >> -- >> >> Alex, >> *Dreams can come true – just believe.* >> >> > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- Alex, *Dreams can come true – just believe.*
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