A basic study on antenna selection for loose beamforming in a massive MIMO system

A study on multi-user massive multiple-input multiple-output (MIMO) systems has been done as one of the key technologies for the fifth generation mobile communication system. In massive MIMO systems, more than 100 antenna elements are often used at a base station, and large-dimensional beamforming as multi-user MIMO precoding is needed. Then, heavy computational complexity is a serious issue for multi-user massive MIMO systems. In this paper, we propose a loose beam-forming method only using simple antenna selection focusing on desired signal power. In addition, we evaluate the sum-capacity of the loose beamforming using channel information obtained by a ray-tracing technique. Through the simulation, it has been shown that the performance of the simple antenna selection is better than random selection and show a possibility that the loose beamforming is effective when simple implementation is required.