The multipath performance of a given signal/receiver combination depends on various signal and receiver parameters like signal type/modulation scheme pre correlation bandwidth and filter characteristics, chipping rate of code ,relative power levels o

In OFDM transmission, all the available subcarriers from the DFT is not used for data transmission. Typically some subcarriers at the edge are left unused to ensure spectrum roll off. For the example scenario, out of the available bandwidth from -10M

This coding gives the implementation using three dimensional CDMA technique for multiple access. so that more number of users can be accomadated in the available bandwidth