Adaptive Downlink Power Control for Co-Channel Femtocells in OFDMA Cellular Networks

In this paper, we derive the outage probability (OP) expressions for co-channel OFDMA macrocell- femtocell networks as a function of femtocell radio parameters and load conditions of neighboring macrocells. From the derived OPs, for a given macrocell network load, we analyze the minimum and maximum transmit power for femtocells that maintains OPs of both macrocell and femtocell users within the acceptable level. The results show that the OP performance in co-channel deployment mode is highly sensitive to macrocell load. It is seen that by dynamically adjusting transmit power of femtocells along with the activity status of suchannels according to varying network load condition, the co-channel interference can be effectively controlled while meeting QoS requirements of macrocell and femtocell users.