Tell me more ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.
up vote 2 down vote favorite

Asked the question here :

I would like to understand Complementary Code Keying. How modulation and demodulation is done ? How higher data rate is achieved using CCK modulation in IEEE 802.11b ?

What is Hadamard transform encoding specified in IEEE 802.11b spec ? How demodulation can be performed on the received samples.

http://stackoverflow.com/q/5551869/630661

share|improve this question
1  
Well, I just developed the code for modulation and demodulation in Matlab using the CCK Encoding table. Just in case, if someone is interested, here is the code for the CCK encoding table: matlab.my/hj870O – Kiran Chandrashekhar Apr 19 '11 at 14:26

1 Answer

up vote 2 down vote

max CCK = 11 Mbps 4 Msymbol/s QPSK like symbols spread by 8 chip due to adjacent chan. interference.

For faster rates, CCK is used to transmit the packet preamble/header and OFDM is used to transmit the payload up to 54 Mbps. The header contains the payload length, so all other receivers know to keep quiet during transmission to prevent direct collisions. They also use RTS/ CTS packets so units far from each other hear the shared router control packets.

There are many design block diagrams on how they radios work on the web.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.