Multi-Flow Glossy: Physical-Layer Network Coding Meets Embedded Wireless Systems
Abdelrahman Abdelkader, Johannes Richter, Eduard Axel Jorswieck, Marci Zimmerling · Zenodo (CERN European Organization for Nuclear Research) · 2017
Emerging applications like wireless control or drone swarms require low-latency communication across multiple hops among a large number of both static and mobile devices. Recent protocols based on synchronous transmissions can meet most of these requirements. In particular, Glossy comes extremely close to the minimum lower latency bound for flooding a single packet. However, when multiple packets need to be exchanged, the overall latency increases linearly since each packet must be mapped onto a distinct Glossy flood. This paper explores the opportunities and challenges of physical-layer network coding to exchange more packets per unit of time. To this end, we present Multi-flow Glossy (MF-Glossy), a communication scheme that simultaneously floods different packets from multiple sources to all nodes in the network. We determine upper bounds on the performance of Glossy and MF-Glossy using a communication-theorectic analysis. Further, we show by simulation that MF-Glossy has the potential to achieve several-fold improvements in goodput and latency across a wide spectrum of network configurations at lower energy costs and comparable packet reception rates. On the road to harnessing this potential in real low-power networks, we demonstrate a proof-of-concept implementation on software-defined radios, and discuss the key research challenges and possible solutions lying ahead.