Hi fellas, I am doing CCK demodulation by 802.11 standard. I have a signal which is a real WLAN packet but i am doing the decoding off line. My original goal is to do this online with a DSP but intially i am saving the packet and doing decoding offline. I know where the CCK modulation starts in a WLAN packet so i starts decoding from that very instant. My operation steps are listed below: 1. I downsample my data from 200Mbps to 11 Mbps 2. At 11Mbps, i add I and Q component and divide the whole packets into octets. 3. I take the first octet, multiply it with the whole RAKE matrix and find out which bit combinations were used for d2.....d7. 4. I do this operation for all octets and fin out d2....d7 for all octets. 5. To calculate d0 and d1, i go back at the product out put of RAKE matrix and choose the maximum product(which is a complex number). I do this for all incoming octets. 6. I take alll these results of rake multiplication, pass it through a DQPSK demodulator and for every single input , i found d0 and d1. i attach this to d0 and d1 to d2...d7 and complete all my octets this way. 7. I passed them finally through a descrambler to find original bits. The problem is very simple that my result doesnot match with the original input which i know what is. But the reason of teh problem, i cant figure out. Can some one find out any mistake in the above proceure, am i missing some thing.? br

# CCK demodulation

Started by ●December 18, 2007