The characteristics of a multipath indoor optical wireless channel can be estimated by two parameters: optical channel path loss (OCPL) and the root mean square (RMS) delay spread. In this letter, an optimized Gaussian beam (OGB) is proposed for a cellular indoor optical wireless communications (CI-OWC) system. The expression for OGB with an optimized beam waist radius for OGB is derived. OCPL and the RMS delay spread (Drms) for four different configurations are simulated and analyzed. Results show that, for a CI-OWC system, a minimum OCPL can be achieved by using the OGB and the maximum transmission data rate can be significantly extended by increasing the number of cells.