可见光无线信能同传网络中能量有效的波束赋形设计

Internet of Things (IoT) is a key application of future 6G. However, it is challenging to provide high-quality wireless coverage for billions of IoT devices with limited Radio Frequency (RF) bandwidth. Visible Light Communication (VLC) utilizes abundant ultrahigh bandwidths as complement to RF communication. This paper investigates the Energy Efficiency (EE) of a Simultaneous Lightwave Information and Power Transfer (SLIPT) enabled multi-user VLC system. An EE maximization problem is formulated under constraints of Quality of Service (QoS) requirements of energy harvesting and information rate at users, avoiding clipping distortion by the nonlinearity of the LED and the power budget at VLC transmitter. To solve the considered problem, an iterative algorithm is proposed based on Dinkelbach and successive convex approximation methods to optimize the beamforming vectors and the direct current offset. The convergence of the proposed algorithm is theoretically proved. The impact of the constraint of avoiding clipping distortion by the nonlinearity of the LED on EE is discussed. Simulation results verify the analysis. Moreover, the impacts of QoS requirements of users, the power budget at VLC transmitter and the filed of view of LED on EE are illustrated and analyzed.