A QoS-Driven Random Access Algorithm for MPR-Capable VLC System

Carrier sensing can mitigate collisions in carrier sense multiple access systems. However, its effectiveness is significantly limited by the directionality of light in visible light communication (VLC) systems. Therefore, in this letter, multipacket reception (MPR) is introduced to weaken collisions for the VLC random access system. We propose a novel quality of service (QoS)-driven non-carrier sensing random access (NCSRA) mechanism for the MPR-capable VLC system. First, we employ the QoS exponent in the effective capacity (EC) theory to characterize the system-level delay-QoS constraint in our system and derive the system EC considering the multiple stochastic characteristics in the NCSRA VLC system (such as the stochastic blocked channel and the random access mechanism). Then, we formulate the QoS-driven NCSRA algorithm as an EC optimization problem (OP) to find the optimum access probability for the system. Finally, the resultant OP is tackled by the invasive weed optimization algorithm.