基于OFDMA子载波功率分配的FFR广义分析模型

Generalization FFR model based on subcarrier power Allocation in OFDMA

基于正交频分多址接入(OFDMA)系统对分数阶频率复用(FFR)技术进行了研究。通过引入功率比值和软频率复用因子的概念,提出了FFR广义分析模型。目前现存的FFR方案均可作为特例统一在该广义分析模型的框架之下。该模型从OFDMA子载波功率分配的角度出发,为分析FFR提供了一种新的视角。理论分析表明,可以通过调整功率比值连续地调整软频率复用因子。对于基于FFR的OFDMA蜂窝系统,通过该模型可以有效地平衡小区容量和覆盖之间的矛盾。最后,基于全球互操作性微波接入(WiMAX)系统,从计算机仿真的角度证实了该结论,同时给出了功率比值的合理取值范围,这对于实际系统的设计颇具指导意义。

Based on orthogonal frequency division multiple access （OFDMA） cellular systems, the paper studies the fractional frequency reuse （FFR） fechnique in detail. By defining the concepts of power ratio and soft frequency reuse factor, a generalized FFR model is proposed. Moreover, all the existing FFR schemes can be considered as its special cases. The model originates from the subcarrier power allocation in OFDMA, and provides a novel perspective on FFR. The theoretical analysis shows that the soft frequency reuse factor can be adjusted smoothly as power ratio varies continuously. For FFR-based OFDMA cellular systems, the tradeoff between cell capacity and coverage can be efficiently balanced by the model. Subsequently, based on worldwide interoperability for microwave access （WiMAX） systems, the simulation was conducted and the results agreed well with the theoretical analysis in the study. Finally, an effective range for power ratio was presented, which is very instructive to practical system design .