Analytical Evaluation of Offloading Gain in Macrocell-Femtocell OFDMA Networks

Orthogonal Frequency Division Multiple Access (OFDMA) based mobile networks are expected to provide increased system capacity by offloading traffic from existing macro cells. However, the gain may be limited due to random and uncontrolled interference caused by dense deployment of femtocells particularly in co-channel deployment mode. In this paper, we present an analytical framework to evaluate the capacity enhancement of the OFDMA-based co-channel macrocell-femtocell networks. We study the throughput performance and investigate the achievable offloading gain in terms of number of supportable users in the system. We also study the impact of macrocell power configurations on the performance of the network. It is seen that the macrocell offloading gain increases with femtocell density and the performance of the network is heavily influenced by macrocell power configuration and load condition. The results show that, in co-channel deployment mode, offloading gain can be improved by choosing appropriate femto load and femtocell transmit power according to the network traffic condition.