Re: Cyclic Prefix
Hi
I agree with Kamal and Trying to make it more clear
No channel Equalizer is used in OFDM and CP is used instead to avoid ISI
See the attached Pic
The OFDM theory requires that a Cyclic Prefix (CP) must be added at the beginning of the OFDM symbol.
the CP allows the receiver to absorb much more efficiently the delay spread due to the multipath and to maintain frequency orthogonality.
The CP that occupies a duration called the Guard Time (GT), often denoted TG, is a temporal redundancy that must be taken into account in data rate computations.
The ratio TG/Td is very often denoted G in WiMAX/802.16 documents.
if the multipath effect is important (a bad radio channel), a high value of G is needed, which increases the redundancy and then decreases the useful data rate; if the multipath effect is lighter (a good radio channel), a relatively smaller value of G can be used.
Salam
Hossam Alzomor
www(.)i-g(.)org