This paper proposes a novel address mapping mechanism for multi-robot communication and collaboration systems, named SPing. SPing addresses each robot with a dynamicphysical-world address- an encoding of the robot's physical location - rather than a pre-assigned digital-world ID (e.g., the IP address). This enables a “see-and-point” communication mode for robots: a robot can establish an immediate connection pointing to any other robot it intends to collaborate with in its visual field, without relying on a pre-existing multi-robot network. This on one hand improves the robustness and usefulness of multi-robot systems in uncertain and unstructured environments where network infrastructures are unavailable. On the other hand, it makes the robots' communication behavior tightly coupled with and more supportive of the collaboration tasks in the physical world. We build an end-to-end prototype of SPing and evaluate its performance in both static and mobile scenarios. The results show that SPing can always establish a connection precisely pointing to the target receiver with an average matching rate of 99.58%, and a spatial resolution of 0.3 m$\sim$0.5m.

This paper tries to answer a question: “Can we achieve spatial-selective transmission on IoT devices?” A positive answer would enable more secure data transmission among IoT devices. The challenge, however, is how to manipulate signal propagation without relying on beamforming antenna arrays which are usually unavailable on low-end IoT devices. We give an affirmative answer by introducing SpotSound, a novel acoustic communication system that exploits the diversity of multi-path indoors as a naturalbeamformer. By judiciously controlling the way how the information is embedded into the signal, SpotSound can make the signal decodable only when the signal propagates along a certain multipath channel. Since the multipath channel decorrelates rapidly over the distance between receivers, SpotSound can ensure the signal is decodable only at the target position, achieving precise physical isolation. SpotSound is a purely software-based solution that can run on most IoT devices where speakers and microphones are widely used. We implement SpotSound on Raspberry Pi connected with COTS microphone and speaker. Experimental results show that SpotSound could precisely focus its signal on spots with customized sizes ranging from 0.04m2to 0.5m2.

This paper tries to answer a question: "Can we achieve spatial-selective transmission on IoT devices?" A positive answer would enable more secure data transmission among IoT devices. The challenge, however, is how to manipulate signal propagation without relying on beamforming antenna arrays which are usually unavailable on low-end IoT devices.