Hello Marcus Thanks for your reply. I'll look into your advice, sounds doable.
Indeed in the past days I was thinking how to make good use on my USRP +WBX to setup a testbench for smart applications using The Things Network (thethingsnetwork.org) with Arduino UNO. I will post my progresses. Cheers Alberto ---------Original message--------------------- Date: Sat, 24 Oct 2015 13:43:40 +0200 From: Marcus Muller <marcus.muel...@ettus.com> Hi Alberto, I think that sounds like a fun project. The LoRaWan website is a little vague till you find the specs [1], and even they do not cite a full PHY document, but a quick patent search helped me find out that it's a Chirp spread spectrum modulation, which led me to Semtech's Application Note 1200.22 . Basically, take your symbol-to-be-transmitted, spread it by transforming it to a series of up- or downchirps, for the LoRa modulation (there's also a GFSK option for some bands as per the LoRaWan spec So: First approach would probably be to take a good-SNR RX signal, filter it to the channel BW; apply "quadrature demod"; a positive value of phase difference would mean "up-chirp", a negative "down-chirp". Slice as appropriate. Altenratively: Apply correlation with chirp, detect whether same "direction" or reversed (maybe something like: signal->FFT (lenght=chirp duration*f_sample)->multiply_const (const = conj(dft(ideal chirp)), vlen=fftlen) ->sum of vector->slicer)) Cheers, Marcus _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
