Abstract:

The application of adaptive allocation techniques to OFDM (Orthogonal Frequency Division Muhiple.xing)systems optimizes the use of system power.In this paper,a subcarrier allocation algorithm based on the re-quired data rates of the users and the characteristics of the channels is proposed by analyzing the power optimization problem.In the proposed algorithm,the subcarrier number finally allocated to each user does not need to be calcu-lated and the allocation process is divided into two steps,namely,the basic allocation and the residual allocation.In the basic allocation,the data of each user is transmitted in time ,and in the residual all ocation.the subcarriers are allocated to users according to the principle of reducing the achievab le minimum transmission power required by each user·Simulated results show that the proposed algorithm can efectively reduce the transmission power

Key words: Orthogonal Frequency Division Multiplexing, multiuser, subcarrier allocation, channel gain