Beam allocation and performance evaluation in switched-beam based massive MIMO systems

This paper focuses on the beam allocation problem with the target of maximizing the sum rate in a switched-beam based massive multiple input multiple output (MIMO) system working at the millimeter wave (mmWave) frequency band. A simple suboptimal beam allocation algorithm is developed, whose average sum rate performance is shown to be nearly optimal while the complexity is greatly reduced. Different from conventional switched-beam systems, with a large number of beams in the massive MIMO systems, the inter-beam interference closely depends on the beam allocation result. By adopting the suboptimal beam allocation algorithm, the effect of the inter-beam interference is investigated through simulations. The results further show that the average sum rate increases with both the number of BS antenna elements and the number of users even though the inter-beam interference is enlarged with an increasing number of users.