Distributed Power Control Mechanisms for HSDPA Femtocells

Abstract —Femtocells are low-cost, miniature base-stations intended to improve indoor coverage in 3Gnetworks and beyond. One of the main issues in adopt-ing femtocells en masse is the surge in interferenceto the mobile users served by the macrocell arisingfrom unplanned networks and private access. Therefore,distributed power control mechanisms for femtocells areessential to shield the existing users of the macrocellas well as to enable scalable femtocell deployments.This paper studies several such power control schemesthat strike an effective balance between the throughputof the femto users and the degradation in macrocellperformance. I. I NTRODUCTION Recent years have witnessed price-wars amongvoice operators, and inspite of increasing number ofsubscribers, the average revenue per user (ARPU)for voice is declining [1]. Operators are starting tofocus on home services, through bundled offeringswith voice, television, data as the triple play , andmobile access adding a potential fourth dimension.But scarce spectrum has pushed 3G and 4G wirelesstechnologies to operate at 2 GHz and above. This, inturn, will lead to spotty coverage for indoor users assignals tend to fade out faster at higher frequencies.