Hi Johannes, I'm back at work after the new year break and have had a chance to try this again, and I think I have it working !! The problem was with my test waveform, I've captured a new test waveform and I can now sync to the DL signal and decode the MIB.
Mike On 21 December 2013 04:26, Johannes Demel <johannes.de...@ettus.com> wrote: > Hi, > > regarding the different parameters. 'tx_diversity' should always be left > as it is. In case of a 1x1 MIMO configuration it will just have no effect. > This parameter reflects the LTE standard with its two options > 'tx_diversity' and 'spatial_multiplexing'. The latter isn't used for > control channels. > In order to specify a certain bandwidth, use the parameter 'N_rb_dl', > which specifies the number of resource blocks used. This will also set the > bandwidth as this is the unit given by the system to determine the > bandwidth. e.g. have a look at the paper which is included in the project > there is a table which shows the dependencies. > 25 RBs --> 25*12 = 300 subcarrier --> 15kHz * 300 + spacing = 5MHz. > The FFT length can be chosen freely as long as it provides sufficient bins > to match the current number of subcarriers. It will be used to determine > the input sample rate. I suggest you stick with power of 2 values. Those > are the only ones I tested and the numbers the system is designed for. One > more thing, a FFT length shorter than 256 results in fractional CP lengths, > which should be avoided. LTE's CP use is already quite tricky and the > introduction of fractional CP lengths will not ease the situation. > PBCH decoding is handled for one and two antenna configurations, so you > don't have to worry about configuring the flowgraph there. > PCFICH decoding will receive a message on runtime which sets the decoded > antenna configuration. > > Happy hacking > Johannes > > > On Fri, Dec 20, 2013 at 2:39 AM, Baier <ba...@irt.de> wrote: > >> Hi Johannes, >> >> thank you very much for updating your gr-lte package. I could compiled >> all .grc files succesfully. Now I would like to test your receiver with a >> LTE signal saved to a file with the following settings.( 5 MHz, RB 25, fft >> 512, occupied carriers 300, no tx diversity). So I have started to change >> the parameters in your grc files. >> RB 25 instead 50 >> fftlen 512 instead 2048(is it right?) >> occupied carriers 300 instead 600. >> So I have realized the files decode_pcfich_37.grc and decode_pbch_37 .grc >> are designed for tx_diversity with two antennas. How can I change it? >> Removing the blocks for the second antenna perhaps? >> Thank you very much. >> A. Baier >> >> >> >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://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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