DC-Bias and Power Allocation in Cooperative VLC Networks for Joint Information and Energy Transfer

Abstract

Visible light communications (VLC) have emerged as strong candidates for meeting the escalating demand for high data rates. Consider a VLC network, where multiple access-points (APs) serve both energy-harvesting users (EHUs), i.e., users which harvest energy from light intensity, and information-users (IUs), i.e., users which gather data information. In order to jointly balance the achievable sum-rate at the IUs and the energy harvested by the EHUs, the paper considers maximizing a network-wide utility, which consists of a weighted-sum of the IUs sum-rate and the EHUs harvestedenergy, subject to individual IU rate constraint, individual EHU harvested-energy constraint, and AP power constraints, so as to jointly determine the direct current (DC)-bias value at each AP, and the users powers. The paper solves such a difficult non-convex optimization problem using an iterative approach which relies on inner convex approximations, and compensates for the used approximations using proper outer-loop updates. The paper further considers solving the special cases of the problem, i.e., maximizing the sum-rate, and maximizing the total harvested-energy, both subject to the same constraints. Numerical results highlight the significant performance improvement of the proposed algorithms, and illustrate the impacts of the network parameters on the performance trade-off between the sum-rate and harvested-energy.

User Pairing, Link Selection, and Power Allocation for Cooperative NOMA Hybrid VLC/RF Systems

“…To harvest the energy in VLC networks, the authors of [21], [22] present and study the concept of simultaneous lightwave information and power transfer (SLIPT) and focus on designing the receiver that realizes SLIPT. The authors of [7] extend the concept of SLIPT to be used in MISO-multiuser VLC system.…”

“…The paper assumes that the strong user can work also as a relay that has the ability to harvest the energy from the light intensity, and then to utilize it to forward the decoded weak user's signal. To harvest the energy, a capacitor separates the DC component from the received electrical signal and forwards it to the energy harvesting circuit [6], [7], [21]. The received energy at the jth user can be expressed as [39]…”

“…which maximizes the total transmit power [7]. Therefore, the maximum allowed deriving power is given by…”

“…Hence, the received visible light at the strong user can be used to charge a power storage and this can be used as a power source to forward the weak user's signal. The energy can be harvested in VLC networks using the received direct current (DC) without affecting the power of the transmitted signal [6], [7].…”

Deep Q-Network Learning Based Downlink Resource Allocation for Hybrid RF/VLC Systems

“…A fixed configuration of power allocation and association parameter has been considered here. In [17], maximization of the total sum-rate in hybrid RF/VLC has been carried out with joint balancing of the individual achievable sumrates of the information UEs and the energy harvesting UEs. The power and the DC-bias of the UEs are optimized while a constant bandwidth and power allocation is considered for the APs.…”