Cross-Tier Interference Mitigation for Two-Tier OFDMA Femtocell Networks with Limited Macrocell Information

Femtocells that use co-channel allocation with macrocells can considerably increase wireless coverage and system capacity, especially for indoor and cell-edge users. However, the benefit is realized only when cross-tier interference between femtocells and macrocells is well managed. We propose a power allocation algorithm for femtocells in downlink OFDMA systems that effectively reduces cross-tier interference by considering the influence on neighboring macro mobile stations (MSs), when only limited channel information about those MSs is available. The use of the proposed scheme enables femtocells to maintain their high throughputs while significantly reducing the performance degradation of neighboring macro MSs, with only the information that is available to the femtocells in practice.