This paper studies the performance of a IoT-relaying node transmission with massive multiple-input multiple-output (MIMO) system network. The system is a simple schematic setup which includes one user, one IoT-relaying node and one base station (BS). The user and IoT-relaying node have a single antenna while the BS is equipped with a hundred and/or even a thousand of antennas array. The transmission protocol is performed based on a very simple amplify-and-forward (AF) relaying scheme. To decode the transmitted signal from the user, the BS applies maximum-ratio (MR) combining technique (the combined channel of the links from the user to BS and the IoT-relaying node to the BS) under assumption of perfect channel station (CSI). The exact closed-form of the throughput and the results for the signal-to-interference-plus-noise ratio (when the number of relay antennas goes to large) are analyzed.