Hi I hope at least one of the members of BBN group read this email. I used BBN implementation of IEEE802.11b to receive packets from commercial products. So I always use Barker code as the spreading key. As it had been reported before, Their code works with 1Mbps and doesn't work with 2Mbps. I cannot understand why. Since bandwidth of DBPSK and DQPSK are the same, the problem is not because of low sampling rate. I went precisely through thier code step by step and everything seems to be correct. In fact, there is a little difference between 1Mbps and 2Mbps modes. To explain the problem clearly I copy and paste results of receiving preamble and header of the short PLCP. You may know that for short PLCP, preamble is sent by 1Mbps while Header is transmitted using DQPSK (2Mbps) and both of them uses Barker code.
Recieved (short) header! signal: 0xBA service: 0xE7 length: 0x640D crc: 0x388A Calculated crc: 0x5112 Recieved (short) header! signal: 0xFF service: 0xCB length: 0x1A50 crc: 0x2C29 Calculated crc: 0x761C Recieved (short) header! signal: 0xF9 service: 0x11 length: 0x8340 crc: 0x8B78 Calculated crc: 0x5D2A Recieved (short) header! signal: 0x31 service: 0x1F length: 0xC729 crc: 0xA902 Calculated crc: 0x255D Recieved (short) header! signal: 0x04 service: 0x09 length: 0x9170 crc: 0xBD57 Calculated crc: 0x67E8 Almost never header is received correctly. I am looking for the reason of the bug. As I mentioned before it is not because of low sampling rate (the sampling rate is 8MSPs) regards, hamed _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
