"No wireless system is known to have such unique characteristics" with James Gross

Wireless networking is known for its salient features such as flexibility and reduction of costs, but it is also known for its inherently unreliable nature. This is witnessed daily by users of mobile networks (such as WLAN or cellular networks) when phone calls are suddenly dropped or web site requests stall in the browser. In regular human-controlled communication (such as phone calls or surfing the web), these errors are annoying, but are typically taken care of by the human user. Nevertheless, the research community in networking is currently working on application paradigms of the next decade, where the fundamental idea is to have computer systems run various autonomic tasks which sense, control and interact with reality. This is widely understood by "Machine-to-Machine Communications" and spans diverse application areas from logistics and health assistance over surveillance to traffic safety, automation in power grids and industrial automation.

 

In general, this novel application class comes with tough challenges for existing networks related to latencies, reliability scalability and energy-efficiency. Especially for traffic safety, automation in power grids and industrial automation, the issues of latency and reliability become most pressing, as wireless systems today do not reach the required levels of reliability in face of deadlines in the range of a few milliseconds. 


This has been the starting point for our research project "EchoRing". EchoRing is a novel protocol family which targets at exactly these two characteristics: Providing extreme levels of reliability at extremely short delays. Potential application domains of our research are autonomous power grids as well as industrial automation systems. EchoRing leverages the usual goal of "maximizing throughput" in wireless networking with reliability at short latencies. It guarantees channel access of all nodes in the system and utilizes various sophisticated means to proactively increase reliability as well as deal with transmission errors once they occurred. The development of EchoRing has been accompanied by the establishment of a precise mathematical model of the protocol and its dynamics based on novel tools from software engineering, which allow to predict performance guarantees of the network depending on the stochastic channel states of the system. 

Apart from the theoretical research, EchoRing has been prototyped and experimental results show that EchoRing achieves reliabilities up to 1 - 10e-7 at latencies in the range of 10ms. No wireless system is known to have such unique characteristics.

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