Energy Efficient Subchannel and Power Allocation in Cooperative VLC Systems

This letter studies the energy efficiency (EE) optimization of cooperative visible light communication (VLC) systems while considering the inter-cell interference and the lineof-sight blockage problems. Specifically, the optimization problem of subchannel and power allocation to maximize EE under transmit power budgets and users' minimum rate constraints is considered. The formulated problem turns out to be a difficult nonlinear fractional program for which a low-complexity iterative solution based on fractional programming theory and the quadratic transform approach is proposed. Extensive simulations are conducted to show the efficacy of the proposed scheme over conventional approaches. In addition, the outage analysis and impacts of varying the transmit power and the subchannel bandwidth on the EE performance are investigated.