Some observations on operating femtocells on the same channel as macro systems based on measurements and simulations

This paper discusses the problems and constraints associated with operating femtocells on the same frequency as the macro system. It addresses questions relating to managing femtocell transmitter power to provide coverage without interfering with the macro system, and to do so especially when the femtocell is located close to a neighboring macrocell. It discusses techniques that can be used to better manage both coverage and interference in co-channel deployments. The basic theory applies to both CDMA-2000 and UMTS/WCDMA technologies. The paper is based on a series of measurements conducted with multiple operators in the US, Europe, and Israel, over approximately 2 years, and a body of simulations of coverage and interference.