Soft frequency reuse design to reduce inteference in femtocell systems

Femtocell is an important solution for operator to enhance the indoor coverage problem and reduce traffic within macrocells. However, there is an ICI (Inter-Cell Interference) between macrocells. Whileas femtocells are located in macrocells environments, CCI (Co-Channel Interference) may occur between femtocells and maceocells. ICI and CCI degrade the performance of femtocell and macrocell. SFR (Soft Frequency Reuse) is effective to improve interference. General SFR is reuse factor 3 but we propose a femtocell allocation method in macrocells environments based on SFR of reuse factor 4. We compare the blacking rate of SFR of reuse factor 3 and SFR of reuse factor 4. Simulation results show that the proposed femtocell deployment shceme does not increase the total blocking rate dramatically but reduce blocking rate of edge users efficiently.