Bounding SINR with the constraints of an optical wireless channel

Signal to interference plus noise ratio (SINR) is an essential metric for performance prediction of wireless communication networks in the presence of multiple transmitters. In such networks, performance analysis and system provisioning often rely on an evaluation of SINR throughout the environment. When calculating SINR, interference and noise variance should be characterized in order to determine the aggregate disturbance. The electrical power constraint in RF communications directly relates to the variance of the interference; however, the variance of an interfering IM/DD optical wireless (OW) signal cannot be directly related to average optical power constraints without knowledge of the modulation scheme. In this paper, we evaluate theoretical upper bounds on the variance of interfering signals and the associated lower bounds on SINR under the constraints of an OW channel. We show how these bounds relate to common OW modulation schemes and illustrate how the bounds can predict worst case performance in scenarios where the composition of the interfering signals is not defined.