Adaptive Resource Allocation Algorithm Based on Cross-Entropy Method for OFDMA Systems

The cross-entropy (CE) method was proposed to estimate the probability of rare events. Afterwards, it was applied to solve combinatorial optimization problems. This paper presents a CE-based method that adaptively allocates sub-carrier, bit, and power in orthogonal frequency division multiple access systems to obtain minimum total transmit power under given quality of service requirements, that is, the minimum data rate and the bit error rate. The proposed scheme first converts the sub-carrier and bit allocations of various users into a binary sequence. Then, a CE-based method is proposed to minimize the total transmission power. Compared with the well-known genetic algorithm and the traditional heuristic algorithm, the proposed scheme has achieved the lowest total transmission power with a few iterations.