In this paper, a novel beam power adaptation method is proposed, studied and shown to be a desirable means for improving the performance of an optical wireless (OW) system that operates under the constraints of background noise, multipath dispersion, and mobility. We propose and evaluate a new OW configuration that employs an adaptive beam clustering method (ABCM) in conjunction with diversity detection. Our goal is to reduce the effect of transmitter/receiver mobility and the associated impacts in terms of a weak received optical power and reduction in bandwidth. Previous work has shown that multiple spot diffusing techniques suffer from these two fundamental limitations associated with mobility. Our new ABCM can help overcome the impairments introduced by mobility, introduce gain in the received optical power, and increase bandwidth even at large transmitter and receiver separations. Our results indicate that, at the least successful locations, the ABCM system can reduce the signal delay spread by nearly a factor of twenty and enhance the SNR by almost 15 dB over a line strip multibeam system (LSMS). We also incorporate the concept of relaying into the Adaptive line strip multibeam system and prove that this technique can lead to considerable performance improvements.