Scrive Eric Blossom <[EMAIL PROTECTED]>: > On Thu, Feb 28, 2008 at 12:51:18PM +0100, Crespi Floriana wrote: > > Hi, > > I have a problem with OFDM system. > > I transmit OFDM signal at 2.4 GHz, but I receive half of the total packets. > > Moreover, only half of the packets received are correct. > > CRC controller is perfect but i want a ber estimate, so I change the > > payload (binary file) and I receive check bit by bit. > > The result of my alteration test is similar than CRC test. > > I have a lot of frequency offset, therefore I change manually the frequency > > receiver. > > I use revision 6845 and RFX 2400. > > Example with crc: > > The final packet I receive: > > ok: False pktno 4602 n_rcvd 1300 n_right 83 > > > > Why can't i get all the packets? > > Could you help me?? > > > > I'm testing OFDM system without USRP and none of the packets are lost. > > > > Thanks a lot. > > > > Hi Crespi, > > You have neglected to tell us virtually anything about your problem. > Could you please tell us: > > which version of GNU Radio? trunk, tarball (which one), etc? > what operating system, distribution and architecture? > the command line you issued > any modifications you may have made to distributed code? > anything else that might be relevant > > > Thanks, > Eric > >
Hi, thank you for your reply. I use: * Linux K-Ubuntu 7.04 *Gnuradio Trunk 6845 The command are : --TX-- sudo python benchmark_ofdm_tx.py -f 2.442e9 -T A --tx-amplitude 10000 --RX--> sudo python benchmark_ofdm_rx.py -f 2.4419899e9 -T A (occuped tones, size packet and fft are default value) Important: If I don't change Rx frequency it can't receive!! I change the payload. I upload file to the code and I calculate its lenght. Number packets= (lenght file/ size packets)+1 Before my modification I tested ofdm system and the result is similar then after modification. The trial simulation (without USRP and antennas) is perfect. I Receive all packets and they are correct. I tested with coax for estimate channel problem but the result is similar to real channel. I thought the problem was the channel but this experiment reject my theory. I don't find the problem because my alteration code don't change the core code. This is my result. final packet =================================================================================== Trial simulation ok: True pktno: 4609 n_rcvd: 4610 n_right: 4610 bit right 14750243 bit wrong 0.0 =================================================================================== All correct =================================================================================== Coax ok: False pktno: 4000 n_rcvd: 1300 n_right: 830 bit right 2109817 bit wrong 2050183 =================================================================================== Thank you a lot for your help. _________________________________________________________________ _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
