Radiation Control Algorithms in Wireless Networks

Electromagnetic radiation, defined as the total amount of electromagnetic quantity that a target elementary surface is exposed to, is one of the main byproducts from the advancement and wide deployment of wireless distributed systems and ad hoc networks consisting of increasingly more powerful devices and diverse technology. Nevertheless, the extreme benefits of the latter have resulted in the emergence of a new research area in algorithmic network design, with main objective the control of the emitted radiation within such systems. In this chapter, we explore this new research area by presenting two quite distinct approaches for radiation control in wireless distributed systems. In particular, we first study the minimum radiation path problem of finding the lowest radiation trajectory of a person moving from a source to a destination point within the area of a network of wireless devices; this is particularly relevant in smart buildings. Second, we study the problem of efficiently charging a set of rechargeable nodes using a set of wireless energy chargers, under safety constraints on the electromagnetic radiation incurred. For both these problems, we provide hardness indications and theoretical results highlighting interesting structural and algorithmic properties. Furthermore, we present and analyze efficient algorithms and heuristics for approximating optimal solutions, namely minimum radiation trajectories and charging schemes, respectively. Finally, we present experimental evidence that not only verifies our theoretical results but also provide new insights that we could not obtain through analysis due to the inherent complexity of these problems.