about 802.11b CCK 5.5Mbps

[qiqi6416]

Hi, everyone. I am sorry if this post should not appear here, but I cann't find a proper place to put this question.

Is there anyone could help me to understand CCK? I mean the procedures of a CCK operation, espacially the 802.11b 5.5Mbps Mode.

it is said that the first two bits (d0, d1) of the symbol is used to determine the vector rotation phase, as


Dibit (d0, d1) Even symbols phase chang(+jw) Odd symbols phase change(+jw)
00 0 pi
01 pi/2 -pi/2
11 pi 0
10 -pi/2 pi/2

the CCK encoding table:
d2d3 c1 c2 c3 c4 c5 c6 c7 c8
00 j 1 j -1 j 1 -j 1
01 -j -1 -j 1 j 1 -j 1
10 -j 1 -j -1 -j 1 j 1
11 j -1 j 1 -j 1 j 1

assume the input data stream is: 01101100 then what is the output stream after CCK coding.

My question is how does (d0, d1) rotat the whole vector? what is the I output and Q output of the complex code? what about the waveform looks like?

 

[bizoo]

well its an old thread but i am also interested to know how dibits d0 and d1 rotate the whole vector,
i know that the phase of d0 and d1 is present in every chip of the codeword of CCK, but what does it mean that the presence of this phase rotate the whole vector/

br