Graduate School and Research Center in Digital Sciences

Seminar: Cutting the Last Wires by Wireless Power Transfer and Energy Harvesting

Kaibin Huang - Prof. at Hong Kong Polytechnic University

Communication systems

Date: January 24, 2013

Despite the explosive growth of wireless communications, mobile devices still have to be connected by cables to the electric grid periodically for recharging and cutting these ?last wires? is the theme of this talk. The interruption of mobile services due to dead batteries can cause not only user inconvenience but also severe issues such as financial loss and health threats. The urgency of addressing this issue and the existence of huge market potential have recently motivated active research on wireless power transfer (WPT). It is also believed that integrating WPT and information transfer, namely simultaneous information-and-power transfer (SIPT), will lead to a new revolution in Internet technologies. Besides WPT, wireless networks can be also powered by harvesting energy from the ambient environment. In this talk, I will share my recent research on network designs and resource allocation for WPT, SIPT and energy harvesting. In the first part, I will propose a novel network architecture that overlays a cellular network with randomly deployed fixed station call power beacons (PBs), which wirelessly charge mobiles by microwave power transfer (MPT). Efficient MPT based on this architecture will be feasible for future mobile networks via combining small-cells and massive antennas and the dense deployment of low-complexity PBs. Based on a stochastic-geometry network model, I will show the fundamental tradeoffs between the base-station density and PB density under a constraint on the data-link reliability. In the second part, I will propose a frame work for enabling SIPT in broadband systems based on OFDM and MPT. This framework features a SIPT-enabled mobile architecture and a set of power-control algorithms designed for a comprehensive set of system configurations. Optimizing power control for broadband SIPT results in a new class of multiuser power-control problems featuring the circuit-power constraints, namely that the transferred power must be sufficiently large for operating receiver circuits. Last, I will consider a mobile ad hoc network powered by energy harvesting. In this research, the network is modeled using a Poisson point process and random energy arrivals at transmitters are modeled as stochastic processes. Based on this model, the relation between the dynamics of harvested energy and the active transmitter density is established and applied to derive the maximum network spatial throughput for a given energy arrival rate.

Cutting the Last Wires by Wireless Power Transfer and Energy Harvesting