Adaptive Procedure Combining Adaptive User Grouping and Bit- Loading in a Go-mc-cdma

Multi Carrier CDMA (MC-CDMA) has shown better results than conventional OFDM systems due to the frequency diversity we achieve with frequency spreading. This spreading is more effective whichever better subcarrier states are found. So the optimal approach should load the subcarriers adaptively according to the subcarriers state. In this paper we investigate the use of adaptive grouped multicarrier CDMA with adaptive modulation for the downlink with the aim of increasing the system’s user-capacity while maintaining a satisfactory BER performance. This scheme allocates the users in their best subcarriers and loads the optimal number of bits per symbols to assure a certain BER.