Joint power allocation and splitting (JoPAS) for SWIPT in doubly selective vehicular channels

In recent years, the capacity and charging speed of batteries have become the bottleneck of mobile communications systems. With the development of wireless power transfer technologies, simultaneous wireless information and power transfer (SWIPT) emerges as a potential solution for green communications. Due to hardware limitations, the energy harvesting circuit cannot decode the signal directly. Power splitting is a popular and effective solution to this problem. Consequently, the problem of optimal power splitting at the receiver arises in addition to the conventional problem of power allocation in communications systems. SWIPT in vehicular networks is a promising technology that helps extend the lifetime of sensors installed on vehicles and roadside units. However, existing SWIPT schemes fail to consider the doubly selective characteristics of vehicular channels. In this paper, joint power allocation and splitting for SWIPT over such channels is proposed with the objective of maximizing the achievable data rate with constraints on the delivered energy. Simulations show significantly improved performance compared with the existing dynamic power splitting scheme. A suboptimal algorithm, named decoupled power allocation and splitting, is also proposed with significantly reduced computational complexity and simulations demonstrate its near-optimum performance.