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 <manu.t.s...@gmail.com> 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 <cingular.a...@gmail.com>wrote: > >> Seems no one can shed a light on this topic? >> >> >> On Thu, Feb 28, 2013 at 10:25 PM, Alex Zhang <cingular.a...@gmail.com>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.* >>> >> >> >> >> -- >> >> Alex, >> *Dreams can come true – just believe.* >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > > > -- > Manu T S > -- Alex, *Dreams can come true – just believe.*
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