Abstract: In this letter, we analyze cluster characteristics and millimeter wave channel characteristics based on an indoor channel measurement campaign at 28 GHz. The spatial properties of clusters are analyzed, and we investigate the intra-cluster angular spreads and the number of clusters. Also, we introduce the random cluster number (RCN) feature to the primary module of the International Mobile Telecommunications (IMT)-2020 channel model. The RCN is based on a Poisson distribution to simulate the evolution of clusters above 6 GHz to get distributions closer to real channel conditions. Examples of the singular value distributions with and without the RCN feature are given. From the comparisons, we can see the benefits of using the RCN feature in simulations with the IMT-2020 model.