A Cross-Layer Fair Resource Allocation Algorithm for OFDMA Systems

The rate adaptive resource optimization problem in OFDMA systems is addressed. A novel cross-layer subcarrier and bit allocation algorithm is proposed, which aims to maximize the system throughput with the overall transmit power constraint and user rate proportionality constraint. Different from existing non-cross-layer methods, the algorithm makes allocation policy based on not only channel condition but also queue status of each user. The algorithm consists of two steps. Firstly, subcarriers are assigned to users under the proportional rate constraint and queue length constraint, assuming that the power is uniformly allocated on each subcarrier. In the second step, the overall power is allocated via a proposed proportional greedy algorithm, with the consideration of buffer state information as well, which can increase the power usage efficiency in some cases. Simulation results show that the proposed cross-layer algorithm achieves a better performance than existing non-cross-layer algorithms