Adaptive Block-Level Resource Allocation in OFDMA Networks

In this paper, we investigate adaptive resource allocation in downlink transmission of orthogonal frequency division multiple access (OFDMA) networks. A block-level resource allocation scheme is developed to maximize the overall throughput of the networks. We focus on application in long term evolution (LTE) systems where all resource blocks (RB´s) allocated to the same user must use the same modulation and coding scheme (MCS). The complexity of such optimization problem is usually high. In order to reduce the complexity, we divide the original optimization problem into two suboptimal ones. We first allocate appropriate RB´s to users with the best channel quality and then perform power allocation. Finally, a more effective MCS is selected, which not only ensures block-error rate (BLER) performance of RB with the poor channel condition but also makes full use of the RB´s with good channel condition. Simulation results show that the proposed resource allocation scheme can improve the overall throughput of the network by 20% compared with the existing scheme when the number of users is 4 and SINR = 10 dB.