Low-Complexity Resource Allocation in Rate-Constrained OFDMA Downlink Systems

A resource allocation algorithm, which provides Quality of Service (QoS) guarantees to users, in a cellular orthogonal frequency division multiple access (OFDMA) network is proposed. The algorithm is a modified water-filling algorithm. In the first phase, power and sub carriers are allocated together, and in the second phase, users' minimum data rate requirements are met, while the remaining resources are allocated in order to maximize sum rate. It is a cell-level algorithm, and its main advantages are the low implementation complexity and the capacity of maintaining higher ratio of QoS satisfied users. Via simulation, this scheme outperforms other proportional resource allocation schemes.