In recent years, optical wireless communication (OWC) has been presented as a viable and promising technology to achieve a high-speed indoor wireless link. In this paper, to fully exploit the advantages of OWC, an optimal Lambertian order (OLO) and a handover algorithm are proposed and adopted for a cellular indoor OWC system to further extend the transmission bandwidth. We firstly describe these two techniques for a cellular configuration. Then, the channel characteristics including the optical power distribution and the RMS delay spread for a four-cell structure are simulated and analyzed. The results show that with an OLO and a handover algorithm applied on the link, the transmission bandwidth of the system can be extended by almost ten times compared to the non-optimized scenario. However, the improvement contributed by the handover algorithm depends on the numbers of the cells and the locations of the users as well.