Orthogonal mean that peak of one carrier is exactly overlapping over null of all other carrier.so called orthogonal. because as when two signal start one from origion and one from 90 deg here is also same. there difference is 90 degree so called ortgogonal.
I see.. but in that case we have overlapping between channels.. and consequent interference.. why is the OFDMA used? Which application? I saw it is adopted for VaNet opportunistic networks but I don't see the benefit..