Full TCP/IP for 8-Bit architectures

We describe two small and portable TCP/IP implementations fulfilling the subset of RFC1122 requirements needed for full host-to-host interoperability. Our TCP/IP implementations do not sacrifice any of TCP's mechanisms such as urgent data or congestion control. They support IP fragment reassembly and the number of multiple simultaneous connections is limited only by the available RAM. Despite being small and simple, our implementations do not require their peers to have complex, full-size stacks, but can communicate with peers running a similarly light-weight stack. The code size is on the order of 10 kilobytes and RAM usage can be configured to be as low as a few hundred bytes

A Low-Overhead Script Language for Tiny Networked Embedded Systems

With sensor networks starting to get mainstream acceptance, programmability is of increasing importance. Customers and field engineers will need to reprogram existing deployments and software developers will need to test and debug software in network testbeds. Script languages, which are a popular mechanism for reprogramming in general-purpose computing, have not been considered for wireless sensor networks because of the perceived overhead of interpreting a script language on tiny sensor nodes. In this paper we show that a structured script language is both feasible and efficient for programming tiny sensor nodes. We present a structured script language, SCript, and develop an interpreter for the language. To reduce program distribution energy the SCript interpreter stores a tokenized representation of the scripts which is distributed through the wireless network. The ROM and RAM footprint of the interpreter is similar to that of existing virtual machines for sensor networks. We show that the interpretation overhead of our language is on par with that of existing virtual machines. Thus script languages, previously considered as too expensive for tiny sensor nodes, are a viable alternative to virtual machines

The ContikiMAC Radio Duty Cycling Protocol

Low-power wireless devices must keep their radio transceivers off as much as possible to reach a low power consumption, but must wake up often enough to be able to receive communication from their neighbors. This report describes the ContikiMAC radio duty cycling mechanism, the default radio duty cycling mechanism in Contiki 2.5, which uses a power efficient wake-up mechanism with a set of timing constraints to allow device to keep their transceivers off. With ContikiMAC, nodes can participate in network communication yet keep their radios turned off for roughly 99% of the time. This report describes the ContikiMAC mechanism, measures the energy consumption of individual ContikiMAC operations, and evaluates the efficiency of the fast sleep and phase-lock optimizations

On-demand Construction of Non-interfering Multiple Paths in Wireless Sensor Networks

In this paper we present a routing scheme for on-demand construction of multiple non-interfering paths in wireless sensor networks. One usage of this multipath scheme is to provide a source the ability to increase the likelihood that its data reaches the sink by sending a copy of a packet on more than one path. The routing scheme is based on the assumption that the sensor nodes are aware of their geographic position

Poster Abstract: Low-Power Wireless IPv6 Routing with ContikiRPL

RPL is the IETF candidate standard for IPv6 routing in low-power wireless sensor networks. We present the first experimental results of RPL which we have obtained with our ContikiRPL implementation. Our results show that Tmote Sky motes running IPv6 with RPL routing have a battery lifetime of years, while delivering 0.6 packets per second to a sink node

Cooja TimeLine: A Power Visualizer for Sensor Network Simulation

Power consumption is one of the most important factors in wireless sensor network research, but most simulators do not provide support for visualizing the power consumption of an entire sensor network. This makes it hard to develop, debug, and understand mechanisms and protocols based on power-saving mechanisms. We present Cooja TimeLine, an extension to Contiki’s Cooja network simulator, that visualizes radio traffic and radio usage of sensor networks. Cooja TimeLine makes is possible to visually see the behavior of low-power protocols and mechanisms thereby increasing the understanding of the behavior of sensor networks. We see this as an important tool for the field moving forward

Improving sensor network robustness with multi-channel convergecast

Intenerg

A Simple and Efficient Method to Mitigate the Hot Spot Problem in Wireless Sensor Networks

Much work on wireless sensor networks deals with or considers the hot spot problem, i.e., the problem that the sensor nodes closest to the base station are critical for the lifetime of the sensor network because these nodes need to relay more packet than nodes further away from the base station. Since it is often assumed that sensor nodes will become inexpensive, a simple solution to the hot spot problem is to place additional sensor nodes around the base stations. Using a simple mathematical model we discuss the possible performance gains of adding these supplementary nodes. Our results show that for certain networks only a limited number of additional nodes are required to fourfold network lifetime. We also show that the possible gain depends heavily on the fraction of nodes already present in the vicinity of the base station

Demo: Snap – Rapid Sensornet Deployment with a Sensornet Appstore

Despite ease of deployment being seen as a primary advantage of sensor networks, deployment remains difficult. We present Snap, a system for rapid sensornet deployment that allows sensor networks to be deployed, positioned, and reprogrammed through a sensornet appstore. Snap uses a smartphone interface that uses QR codes for node identification, a map interface for node positioning, and dynamic loading of applications on the nodes. Snap nodes run the Contiki operating system and its low-power IPv6 network stack that provides direct access from nodes to the smartphone application. We demonstrate rapid sensor node deployment, identification, positioning, and node reprogramming within seconds, over a multi-hop sensornet routing path with a WiFi-connected smartphone

A Low-Power CoAP for Contiki

Internet of Things devices will by and large be battery-operated, but existing application protocols have typically not been designed with power-efficiency in mind. In low-power wireless systems, power-efficiency is determined by the ability to maintain a low radio duty cycle: keeping the radio off as much as possible. We present an implementation of the IETF Constrained Application Protocol (CoAP) for the Contiki operating system that leverages the ContikiMAC low-power duty cycling mechanism to provide power efficiency. We experimentally evaluate our low-power CoAP, demonstrating that an existing application layer protocol can be made power-efficient through a generic radio duty cycling mechanism. To the best of our knowledge, our CoAP implementation is the first to provide power-efficient operation through radio duty cycling. Our results question the need for specialized low-power mechanisms at the application layer, instead providing low-power operation only at the radio duty cycling layer