User Presence and Antenna Efficiency Effects on MIMO Link Performance

We discuss in this paper the effects of antenna efficiency in the presence of a user and on the performance of a multiple-input multiple-output system. The investigation is carried out in different usage scenarios where the antenna efficiency changes significantly from one scenario to another. The propagation channel is defined to include the 3D antenna electromagnetic properties with the 3GPP spatial channel model. We then investigate at a link level using a Long Term Evolution (LTE) link simulator where the antenna and the user are integrated into the link. The analyses are based on channel correlation, channel power transfer factor, and the link throughput. We show the importance of accurately accounting for the antenna efficiency for realistic MIMO link performance. We also show that accounting for the antenna efficiency is a weighted factor defined by the antenna pattern behavior.