Interference Mitigation Based on Femtocells Grouping in Low Duty Operation
Since a large number of femtocells may coexist in one macrocell area, interference management becomes a major issue in the deployment of femtocells, and therefore has been researched actively. In the IEEE 802.16m, one way to mitigate interference is Low Duty Operation (LDO) Mode for femtocells. Femtocell in the LDO mode changes alternately between available interval and unavailable interval. During available interval, femtocell may become active on air interface by transmitting control messages, while during unavailable interval, femtocell becomes inactive on air interface. However, the operation of femtocell in the LDO mode is not efficient, since it still has available intervals even though there are no MSs will access the femtocell in anytime soon.