To satisfy the request of high data rate and high frequency efficiency for new generation communication system

a method of adaptive modulation modes

subcarrier and power allocation is proposed for OFDM-DS/CDMA systems. With the downlink channel parameter acquired from uplink channel feedback

an optimization algorithm is utilized to maximize frequency efficiency and minimize the required transmitting power for a given QoS and data throughput.Compared with non-adaptive OFDM system

the required transmitting power is greatly decreased and the convergence rate of this algorithm is very high which makes it very appropriate for engineering application.