Equal Rate Resource Allocation for Multiuser OFDM

The performance of multicarrier systems can be enhanced by the water filling strategy, in which different rates and powers are allocated to subcarriers. However, the induced large signaling overhead leads to less transmission efficiency. To suppress this effect, this paper proposes an alternative strategy by dynamically assigning the same rate to each subcarrier per user. The authors quantify the asymptotic limits of its instantaneous per-symbol performance loss compared to water filling. Then, they apply this strategy to weighted sum rate maximization subject to minimum required rates and limited transmission power. Due to the simplicity of the proposed strategy, a low-complexity method is given, which can be used for other resource allocation problems in multi-carrier systems with small modifications.