Science Publishing Group
In this paper, the authors present a hybrid multiple access schemes to increase the data rate and to provide more flexibility for 4G wireless communications. The proposed scheme utilizes a combination of the multiple access techniques TDMA, CDMA and OFDMA. It uses variable time slots, spreading factors and number of subcarriers to provide flexible data rates for different classes of users. The performance analysis of the proposed scheme is carried out for different modulation schemes used in downlink and expressions for Multiple Access Interference (MAI) and Bit Error Rate (BER) are derived. The parameters for this scheme are selected depending on available bandwidth, required data rates, number of users, type of service provided etc.