Embedded Wireless Network Research Articles

Model-Based QoS Evaluation and Validation for Embedded Wireless Sensor Networks

Wireless communication technologies have the potential to significantly reduce cabling cost, cut down on weight, and simplify the overall structure of industrial embedded systems. Potential risks and costs of a technological switch from wired interconnections toward a wireless solution are difficult to estimate, however. Model-based system engineering can help to reduce risk and cost and to increase the quality of the resulting system. However, standard network simulation software has to be adapted to the particular requirements of embedded wireless sensor networks such as system operational modes and phases, comprehensive means of configuration, and performance analysis; and models are not easy to validate in detail. This paper presents a highly scalable model for industrial embedded wireless networks to validate different system configurations and applies it to a system setup designed for avionic environments, using a software architectural framework for domain-specific simulation-based tools. The presented model is detailed enough to cover the significant behavior for quality of service requirements, including delays, throughput, reliability, energy consumption, and node lifetime. An additional important contribution is the direct connection between design tool and test bed or prototype system, allowing a seamless configuration of a hardware setup and an integration of measured behavior for a fine-grained validation of model and prototype. The application to a real-life system setup shows the benefits of the integrated approach.

Robust architectures for embedded wireless network control and actuation

Networked cyber-physical systems are fundamentally constrained by the tight coupling and closed-loop control of physical processes. To address actuation in such closed-loop wireless control systems there is a strong need to rethink the communication architectures and protocols for reliability, coordination, and control. We introduce the Embedded Virtual Machine (EVM), a programming abstraction where controller tasks with their control and timing properties are maintained across physical node boundaries and functionality is capable of migrating to the most competent set of physical controllers. In the context of process and discrete control, an EVM is the distributed runtime system that dynamically selects primary-backup sets of controllers given spatial and temporal constraints of the underlying wireless network. EVM-based algorithms allow network control algorithms to operate seamlessly over less reliable wireless networks with topological changes. They introduce new capabilities such as predictable outcomes during sensor/actuator failure, adaptation to mode changes, and runtime optimization of resource consumption. An automated design flow from Simulink to platform-independent domain-specific languages, and subsequently, to platform-dependent code generation is presented. Through case studies in discrete and process control we demonstrate the capabilities of EVM-based wireless network control systems.

Ubiquitous networks and their applications

Improvements in microprocessor and radio technologies have led to an increasing interest in wireless networking. At the same time, personal digital electronics have become widespread. To the enthusiast these two trends immediately bring to mind a wide range of esoteric applications. Commercially, by contrast, few substantial applications for embedded wireless networks have been proposed. This article describes the Prototype Embedded Network (PEN), a short-range low-power wireless network specifically designed to be a ubiquitous first point of contact between any and every kind of device. We describe some of the key technical issues encountered in PEN's development and illustrate these by example with applications we have built.