Virtual Coordinate Systems and Coordinate-Based Operations for IoT

Abstract

Driven by increasing potency and decreasing cost/size of electronic devices capable of sensing, actuating, processing, and wirelessly communicating, the Internet of Things (IoT) is expected to expand into manufacturing plants, complex structures, and harsh environments. Subnets of simple devices ranging from smart RFIDs and tiny sensors/actuators deployed in massive numbers in 2D and complex 3D physical spaces will be key constituents of this infrastructure. Knowing the position of different devices within such networks is essential for the higher-level applications as well as networking functions. Measuring the physical distances and obtaining geographical coordinates of these devices become very costly, unreliable, or even infeasible for many IoT networks, particularly those deployed in harsh and complex environments that affect distance estimates and other measurements. Virtual coordinate systems (VCS) overcome such limitations and provide a viable alternative to geographic coordinates for many networking applications. They do not rely on received signal strength indicator (RSSI) or time delay, measurement of which is difficult and unreliable. Instead, VCSs use parameters such as connectivity or packet losses to develop coordinate systems which provide the basis for network operations such as self-organization, routing, and topology control. We provide a survey of these VCSs. Four main classes of VCS are defined: coordinate systems based on an embedded graph/tree topology, coordinate systems based on hop distances to a set of anchors, topological coordinate systems, and coordinate systems based on network properties. In addition to that, network operations such as routing based on different coordinate schemes are presented.