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Resource allocation in underwater acoustic OFDMA downlink systems

It is important to effectively allocate resources in an underwater acoustic orthogonal frequency division multiple access (OFDMA) downlink system. Traditional resource allocation algorithms in radio usually have high computational complexity, which is not suitable for the fast time-varying underwater environment. In this paper, a rate adaptive resource allocation algorithm is investigated in which subcarrier and power allocation are carried out sequentially to reduce the process' computational complexity. During the subcarrier allocation, an algorithm based on a rate constrained by what satisfies the minimum rate request is proposed. Then by combining subcarrier allocation and channel state information, an approximate suboptimal power algorithm is proposed. Compared with the root-finding and linear methods, the proposed algorithm has a higher sum rate and relatively lower computational complexity under poor underwater acoustic communication (UAC).