hitman1988
Member level 5
hi all
I was solving a numerical example For OFDM of binary data sequence of 16-bit but I'm facing a little difficulties in some some domins that some DSP operation involved , the example below
data=[1 0 1 0 1 1 1 0 0 0 0 1 0 1 0 1]
S/p output
Ts/p = 1 1 1 1 0 0 0 0
0 0 1 0 0 1 1 1
which is equal to [ 2 2 3 2 0 1 1 1 ]
then we map it in pi/4 QPSK mapper we get
Tmapped = [1-i 1-i -1-i 1-i 1+i -1+i -1+i -1+i ]
then we make the zero pad sequence
0 0 0 0 1 1 -1 -1 -1 1 1 -1 0 0 0 0
0 0 0 0 1-i 1-i -1-i 1-i 1+i -1+i -1+i -1+i 0 0 0 0
here is the problem the first row of zero pad , how to get it , I mean how does it become like this . I know about the the zeros at the beginning and at the end but i can't figure out how the ones and negative ones are come out? please help in this one .
and if any knows the way to calculate the IFFT for the zero pad sequence.
thanks in advance
Mohannad
I was solving a numerical example For OFDM of binary data sequence of 16-bit but I'm facing a little difficulties in some some domins that some DSP operation involved , the example below
data=[1 0 1 0 1 1 1 0 0 0 0 1 0 1 0 1]
S/p output
Ts/p = 1 1 1 1 0 0 0 0
0 0 1 0 0 1 1 1
which is equal to [ 2 2 3 2 0 1 1 1 ]
then we map it in pi/4 QPSK mapper we get
Tmapped = [1-i 1-i -1-i 1-i 1+i -1+i -1+i -1+i ]
then we make the zero pad sequence
0 0 0 0 1 1 -1 -1 -1 1 1 -1 0 0 0 0
0 0 0 0 1-i 1-i -1-i 1-i 1+i -1+i -1+i -1+i 0 0 0 0
here is the problem the first row of zero pad , how to get it , I mean how does it become like this . I know about the the zeros at the beginning and at the end but i can't figure out how the ones and negative ones are come out? please help in this one .
and if any knows the way to calculate the IFFT for the zero pad sequence.
thanks in advance
Mohannad