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An adaptive multicarrier CDMA system is considered. In this system, each user is given a number of codes. Each code essentially creates a different transmission channel for the corresponding user. Each user uses one of the code channels to transmit a data symbol in each symbol interval. At the receiver, the noise and interference level at each code channel is monitored. If the noise and interference level at an available code channel is lower than that in the current code channel, a procedure, called code handoff, would be executed at allowed instants, i.e., the user would switch to the better code channel. Only power control and code handoff, which can be readily implemented, are required in the system. Analysis shows that interference power can be significantly reduced. With suitable choices of the codes, the effects of fading can also be alleviated. Simulations also show that the proposed system performs better than ordinary multicarrier CDMA systems.