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| An Improved Water-filling Algorithm for Discrete Bit Allocation |
| Zhao Li; Sun Xian-pu; Zhang Hai-lin |
| School of Telecommunication Engineering, Xidian University, Xi’an 710071, China |
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Abstract In this paper, an improved water-filling algorithm is proposed for the problem of Discrete Bit Allocation DBA in OFDM systems. The bit-water-level, defined in this paper as the water-filling level under which the power allocated to a certain sub-carrier satisfies the integer bit constraint, is used in the proposed algorithm. First, using the bit-water-levels of the sub-carrier with the maximal channel gain, bits and power are allocated to all the sub-carriers. Then, the allocation results are adapted to satisfy the total transmit power constraint. It is proved that the algorithm yields the optimal solution and its computational complexity depends only on the number of sub-carriers.
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Received: 13 March 2009
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Corresponding Authors:
Zhao Li
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2010, Vol. 32 
