Generalized analysis model for fractional frequency reuse

Fractional frequency reuse (FFR) is an effective technique to mitigate co-channel interference in orthogonal frequency division multiple access (OFDMA)-based broadband cellular systems. In this paper, we present a generalized model for FFR under which all existing FFR schemes can be considered as its special cases. Additionally, quality factor has been proposed to indicate the quality of the subband. An interesting conclusion can be drawn that, as the power ratio in FFR is adjusted continuously, the corresponding quality factor varies smoothly. Subsequently, simulation is conducted based on worldwide interoperability for microwave access (WiMAX), and the result agrees well with our theoretical analysis. Finally, an effective range for power ratio is presented, which is very instructive to practical system design.