A Practical Power Allocation Algorithm for Wireless OFDM Systems

Le DING  Qinye YIN  Yiwen ZHANG  Yinkuo MENG  

IEICE TRANSACTIONS on Communications   Vol.E90-B   No.2   pp.381-384
Publication Date: 2007/02/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.2.381
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
OFDM,  power allocation,  water-filling,  

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A sub-optimal practical computationally efficient transmit power allocation algorithm is proposed under the constraints of data rate and max bit error rate (BER) in OFDM systems. By exploiting the relation between the water-filling level and the data rate, the proposed algorithm derives an efficient adaptive coarse searching method for water-filling level without need of preset step and other initial parameters, then determines the required water-filling level by the dichotomy method. When the channel state changes, the proposed algorithm works out a small domain of required water-filling level based on the latest allocation and then tracks the channel quickly. Simulation results show that the proposed algorithm converges quickly and is suitable for time-varying channels.