Optical Mobile Communications: Principles, Implementation, and Performance Analysis

Owing to the rapid growth of mobile data communication and spectrum crunch at lower radio frequency, utilizing high frequency spectrum such as millimeter wave for ultra-high data rate mobile communications becomes necessary. Yet the propagation behaviors of high frequency radio waves make mobile communications rather challenging with a lot of technical problems, such as very large propagation loss. In this paper, we propose a novel approach, referred to as optical mobile communications (OMC), to cater to the need for high data rate mobile communication by exploiting optical beams. Taking spatial light modulator as an exemplary means of laser beam adaptation, we first present the system model of OMC. It is shown that the downlink channels in OMC are different from that in a system equipped with antennas emitting radio frequency signals. That is, the OMC channels for different mobile terminals are controllable to a large extent. This new feature creates a new dimension for performance optimization of OMC. We then investigate the achievable rate region of OMC using different multiple access schemes in a two-user downlink system. Numerical results show that expanded rate region can be achieved in OMC compared to the case where channels are not controllable, which shows the potential of OMC as a promising technique.