LTE‐Advanced network inter‐cell interference analysis and mitigation using 3D analogue beamforming

Abstract

This study considers the effects of inter-cell interference (ICI) on the LTE-Advanced physical layer downlink channel for different macro-cell diameters and base station (BS) antenna heights with a frequency reuse factor of one and three sectors per site. A site-specific three-dimensional (3D) ray-tracing tool is used to model the communication channel between the BSs (main and interfering links) and user equipment (UE) terminals. System performance is evaluated in terms of average spectrum efficiency, cell edge throughput and outage probability. Two 3D analogue beamforming algorithms are proposed to mitigate the harmful effects of ICI. These are applied at the BS and/or the UE and compared with a more traditional fractional frequency reuse deployment. Simulations demonstrate that the proposed beamforming algorithms provide significant system level improvements, especially for low BS antenna heights. With 10 × 10 and 2 × 2 antenna arrays at the BS and the UE, respectively, the proposed MaxMin-BF algorithms can provide an average spectrum efficiency of 3.6 bps/Hz and a cell edge throughput of 0.56 bps/Hz up to a cell diameter of 1250 m. Importantly, these results satisfy the IMT-Advanced requirements for candidate fourth generation and beyond radio interface technologies. Furthermore, the performance of proposed beamforming algorithms outperforms those achieved using fractional frequency reuse.