Path-loss Based Power Suppression for Spectral and Energy Efficient Inter-cell Interference Coordination

Abstract

The inter-cell interference problem is a key challenge in OFDMA-based cellular networks because it significantly decreases the throughput of the users at the cell edge. Mitigating this problem requires an inter-cell interference coordination (ICIC) scheme that divides the spectrum into a power constant band and a power limited band for the cell edge users. Overall, static ICIC or frequency reuse schemes are effective when users are uniformly distributed across the network, whilst non-uniform user distributions suggest semi-static ICIC schemes where the power levels in the power limited bands are effectively set based on the interference situation from neighboring cells. In this paper we define a method that uses path-loss statistical measures to describe the non-uniform distribution between adjacent cells. Based on this method, we devise a new distributed algorithm that derives the suppression levels of transmit power a cell may set at a neighboring cell’s cell edge band based on the path-loss to the cell edge users of that neighboring cell. Our algorithm is evaluated by means of simulations and compared to reference frequency reuse schemes based on a non-uniform user distribution scenario where users are distributed in clusters. Simulation results show that the power suppression levels derived by our algorithm greatly improve spectral and energy efficiency as compared to 7-reuse and 1-reuse schemes respectively. It is also shown that our algorithm exploits the non-uniformity in the user distribution to improve the user throughput of cell edge users without any losses in the user throughput of the cell center users. Keywords: ICIC, interference coordination, frequency partitioning, orthogonal frequency division multiplexing (ofdm), soft frequency reuse system capacity, 3GPP LTE standardization.