An Efficient Sub-optimal Subcarrier Allocation Algorithm for Multiuser OFDM System

This paper investigates the allocation of subcarriers and power in the downlink channels of multiuser OFDM systems. The goal is to minimize the total transmit power under the constraints of user data rates and bit error rate (BER). We propose a sub-optimal algorithm to achieve the goal in this paper. We introduce a new factor which is the gain difference between the maximum and the next maximum userspsila channel gains for each subcarrier. Then the subcarriers are allocated to different users according to this factor. The simulation results show this algorithm outperforms the multiuser OFDM systems with static Frequency Division Multiple Access (FDMA) technique, also it outperforms the sub-optimal method proposed by Wong. We quantify the improvement in terms of total required transmit power and BER.