Sectoring in multi-cell massive MIMO systems

Shahram Shahsavari, Parisa Hassanzadeh, Alexei E. Ashikhmin, Elza Erkip

Abstract: In this paper, the downlink of a typical massive MIMO system is studied when each base station is composed of three antenna arrays with directional antenna elements serving 120° of the two-dimensional space. A lower bound for the achievable rate is provided. Furthermore, a power optimization problem is formulated and as a result, centralized and decentralized power allocation schemes are proposed. The simulation results reveal that using directional antennas at base stations along with sectoring can lead to a notable increase in the achievable rates by increasing the received signal power and decreasing `pilot contamination' interference in multi-cell massive MIMO systems. Moreover, it is shown that using optimized power allocation can significantly increase the 0.95-likely rate in the system.