A linear-complexity resource allocation method for heterogeneous multiuser OFDM downlink

In this paper, we consider the dynamic power and rate allocation for the heterogeneous transmission over multiuser orthogonal frequency division multiplexing (OFDM) downlink, where users may require real time or non-real time transmission. The data rate for the real time transmission is lower bounded, while the total transmission power for both transmissions is limited to a fixed amount. Solutions to this problem must be computationally efficient in order to adapt to the fast time-varying channels in practice. To accelerate the resource allocation for the considered scenario, efficient approaches are given to update the power or rate variation while changing subcarrier assignments. By iteratively using these approaches, a resource allocation method is proposed to achieve a good balance between the performance and the complexity. Its complexity is linearly increasing in the number of subcarriers and the number of users. Simulation results demonstrate that our method has small performance loss compared to the dual optimum and achieves much better performance compared to previous works.