On 05/23/2014 02:29 AM, xianda wrote: > Hi: > Thank you so much. > 1.But from "chunks to symbols" I see you use the bpsk and qpsk > both.Right?What is the relationship between 800 bits and 17 > symbols?Namely,how to calculate the 17 symbols? > 17*64=1088.Can you explain?
1 OFDM symbol @ BPSK == 48 bits in this configuration. ceil(800/48) == 17. > 2.I have looked at your ppt about the ofdm.You say now have two version > ofdm.Can you give me some links to them?Or some advices?Thank you. They're both in the tree. If you start working off of rx_ofdm an tx_ofdm you're already using the new stuff; no need to worry about this. M > Best regards > At 2014-05-23 04:33:44,"Martin Braun" <martin.br...@ettus.com> wrote: >> On 05/22/2014 10:12 PM, eontool wrote: >>> IIRC, the tx and rx files are just a very general implementation of the >>> OFDM >>> model. >>> >>> Here's my understanding: >>> >>> - Packet length refers to the data necessary to produce n symbols (48 data >>> carriers, 2 symbols = 96). >> >> Er, no. This is the number of bytes per packet. It's 96 because we add 4 >> bytes for CRC, and then the packet number is a round value. >> >> At 100 bytes per packet, the payload is 800 bits. With BPSK, that would >> be 17 OFDM symbols (plus 1 OFDM symbol for header, and 2 for preamble). >> >> You can set whatever here, but remember that the stock equalizers don't >> do a good job on long packets. Also, the length can vary per packet. >> >>> - The number of total carriers in the systems equals the FFT length. >>> In this case, 48 data carriers and 4 pilots, 52 total and the rest are set >>> to 0. >> >> This is correct (compare 802.11a standard). >> >> M >> >> >> _______________________________________________ >> 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
