Performance Evaluation of Joint Power and Frequency-Domain Intercell Interference Coordination in Heterogeneous Networks

Abstract

We evaluate our previously reported joint power and frequency-domain inter-cell interference coordination (ICIC) method for heterogeneous networks where low transmission-power pico base stations (BSs) overlay onto a high transmission-power macro BS. In the previously reported method, to protect users connected to a pico BS from interference from a high-power macro BS, we define a protected band, which is exclusively used by only pico BSs. In the remaining non-protected band, we employ soft fractional frequency reuse (SFR) at the macro BSs so that macro-to-macro ICIC is achieved. With this frequency usage, we employ adaptive transmission power control for the nonprotected band at the macro BS and simultaneously control the bandwidth allocation to the protected band from the viewpoint of proportional fairness (PF). The previously reported method is achieved with very limited information exchange between BSs. The transmission power control is a decentralized approach. Thus, in this method, we use a cost function in the objective function to lower the transmission power of the macro BSs so that the interference to the other BSs is considered. In our previous investigation, we used different values of the cost for different system conditions. In this paper, we use the same value of the cost for all evaluated conditions to obtain more realistic results. Computer simulation results show in detail the effectiveness of our method compared with conventional approaches under various system conditions.