Downlink Co-tier Interference Mitigation for Femtocell Networks

LTE (Long-Term Evolution) has become the de-facto standard of the fourth-generation (4G) mobile communications which aim at meeting the demands for high-speed data transmission. However, LTE faces signal attenuation and other problems during transmission. FBSs (Femto Base Stations) provide viable solutions to the problems in indoor and urban areas with poor channel quality. But deployment of FBSs causes interference because FBSs are typically installed by end users. In downlink communication, interference can occur between MBS (Macro Base Station) and FBS, or among FBSs. Thus, when an FBS is conducting communication with FUEs (Femtocell User Equipments) under its service in the downlink, how to reduce the interference on other FUEs in order to increase the overall throughput is an important research topic. This paper presents two methods, finding trouble nodes (FTN) and trouble node-aware power back off (TAPB), for achieving the goal. The former is used to identify those FBSs that cause significant interference (trouble nodes) so that power control has to be imposed upon them. The latter is the scheme of actual power control. Results show that the proposed approach is effective in enhancing the throughput of femtocell networks.