An efficient power constrained transmission scheme for hybrid OW/RF systems

This paper investigates link layer transmission schemes for hybrid optical wireless (OW)/radio frequency (RF) systems with constraints on both per-link and total power consumption at the transmitter. Assuming timeslot structure and using a queue for storing the random data packet arrivals, we formulate a stochastic optimization problem where intelligent control decisions are taken by the hybrid transmitter in each slot, regarding the number of the packets admitted in its queue and the power levels used in each link. The aim of this formulation is to design a control policy that maximizes the transmitter throughput, while satisfying its power constraints as well. A solution is offered by using the Lyapunov optimization framework. An on-line transmission algorithm is derived, which takes control decisions based only on the status of the transmitter queue and the erasure probabilities of the OW and RF links. The proposed algorithm meets the desired throughput objective by efficiently exploiting both links, while provides explicit power consumption guarantees.