A subcarrier, bit, and power allocation algorithm for multiuser-based OFDM system

• Main Authors: Jean-Wei Chen, 陳政緯
• Other Authors: Yung-Fang Chen
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/04993542553831797477

碩士 === 國立中央大學 === 電機工程研究所 === 91 === In this paper, we propose a sub-carrier allocation algorithm for OFDM-based multi-user system. Assume that the base station knowing the channel gains of all sub-carriers of all users, we try to minimize the required transmit power while satisfying the users’ rate and bits error rate constraints. The optimum solution of this kind of problem is too complicated to realize. So the DCA [1] (Dynamic Channel Assignment) algorithm based on constructive assignment and iterative improvement is developed to make a solution in real time. But the sub-carrier number of the users can not change according to the fading channel, and the DCA scheme doesn’t say how to decide these numbers also. So this paper proposed a DCA-extension scheme to improve this problem. We add a new factor in the step 2 in DCA, so the user’s sub-carrier number can be adjusted according to the channel fading. Simulation results show that the power gains of this algorithm is proportion to the difference of the users’ SNR and the speed of the users.