ITR/SY: a distributed programming infrastructure for integrating smart sensors

Issued as final reportNational Science Foundation (U.S.

Cyclist training monitoring system based on wireless sensor network

Recent innovation of technology in wireless sensor network (WSN) has eased the deployment of WSN in many applications such as health monitoring system. This research presents a cyclist training monitoring system that is equipped with a set of sensors using the WSN technology. This enables continuous monitoring process of cyclist training that can be done anytime and anywhere. A stable and reliable wireless cyclist monitoring system with minimum data loss is vital to establish a smart and efficient sports management program that can lead to better quality outcomes of cyclist training. This cyclist training monitoring system has been developed and tested in real cyclist training environment in velodrome. The system is designed based on WSN that is linked to the cloud network on the Internet. Using TelG node as the basis, customized transceiver nodes are developed to establish the WSN. These nodes have been built with 30% reduction in size from the existing nodes. Seven measurements were conducted to investigate several factors that affect the packet loss rate before the system architecture was constructed. The factors that were taken into account during the measurements are the distance between the transmitter and the receiver, the height and angle of the receiver, the mobility of the transmitter, the transmission power of the transmitter, as well as the packet size and transmission rate. The results from the measurements correspond to the wireless communication theory. Based on the seven measurements, the system architecture was constructed. Several experiments were conducted in a real scenario in velodrome to measure the reliability of the system architecture. It was shown from the experiments that the proposed system is reliable even when the cyclist is moving at high speed which is 30km/h constantly. The packet loss in all experiments conducted is less than 2%, which does not give huge impact to the sensor data transmission. In addition, the results have shown that the proposed system can produce minimum end-to-end delay which is at 11ms when packet size is below 20 bytes which can be neglected

Availability and End-to-end Reliability in Low Duty Cycle Multihop Wireless Sensor Networks

A wireless sensor network (WSN) is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency is achieved with low duty cycle operation, however, this alone is not enough. WSNs are deployed for different uses, each requiring acceptable Quality of Service (QoS). Due to the unique characteristics of WSNs, such as dynamic wireless multihop routing and resource constraints, the legacy QoS metrics are not feasible as such. We give a new definition to measure and implement QoS in low duty cycle WSNs, namely availability and reliability. Then, we analyze the effect of duty cycling for reaching the availability and reliability. The results are obtained by simulations with ZigBee and proprietary TUTWSN protocols. Based on the results, we also propose a data forwarding algorithm suitable for resource constrained WSNs that guarantees end-to-end reliability while adding a small overhead that is relative to the packet error rate (PER). The forwarding algorithm guarantees reliability up to 30% PER

Designs for the Quality of Service Support in Low-Energy Wireless Sensor Network Protocols

A Wireless Sensor Network (WSN) consists of small, low cost, and low energy sensor nodes that cooperatively monitor physical quantities, control actuators, and perform data processing tasks. A network may consist of thousands of randomly deployed self-configurable nodes that operate autonomously to form a multihop topology. This Thesis focuses on Quality of Service (QoS) in low-energy WSNs that aim at several years operation time with small batteries. As a WSN may include both critical and non-critical control and monitoring applications, QoS is needed to make intelligent, content specific trade-offs between energy and network performance. The main research problem is defining and implementing QoS with constrained energy budget, processing power, communication bandwidth, and data and program memories. The problem is approached via protocol designs and algorithms. These are verified with simulations and with measurements in practical deployments. This Thesis defines QoS for WSNs with quantifiable metrics to allow measuring and managing the network performance. The definition is used as a basis for QoS routing protocol and Medium Access Control (MAC) schemes, comprising dynamic capacity allocation algorithm and QoS support layer. Dynamic capacity allocation is targeted at reservation based MACs, whereas the QoS support layer operates on contention based MACs. Instead of optimizing the protocols for a certain use case, the protocols allow configurable QoS based on application specific requirements. Finally, this Thesis designs sensor self-diagnostics and diagnostics analysis tool for verifying network performance. Compared to the related proposals on in-network sensor diagnostics, the diagnostics also detects performance problems and identifies reasons for the issues thus allowing the correction of problems. The results show that the developed protocols allow a clear trade-off between energy, latency, throughput, and reliability aspects of QoS while incurring a minimal overhead. The feasibility of results for extremely resource constrained WSNs is verified with the practical implementation with a prototype hardware platform having only few Million Instructions Per Second (MIPS) of processing power and less than a hundred kBs data and program memories. The results of this Thesis can be used in the WSN research, development, and implementation in general. The developed QoS definition, protocols, and diagnostics tools can be used separately or adapted to other applications and protocols

On improving the reliability of packet delivery in dense wireless sensor networks

Wireless sensor networks (WSN) built using current Berkeley Mica motes exhibit low reliability for packet delivery. There is anecdotal evidence of poor packet delivery rates from several field trials of WSN deployment. All-to-one communication pattern is a dominant one in many such deployments. As we scale up the size of the network and the traffic density in this communication pattern, improving the reliability of packet delivery performance becomes very important. This study is aimed at two things. Firstly, it aims to understand the factors limiting reliable packet delivery for all-to-one communication pattern in dense wireless sensor networks. Secondly, it aims to suggest enhancements to well-known protocols that may help boost the performance to acceptable levels. We first postulate the potential reasons hampering packet delivery rates with current CSMA-based MAC layer used by the radios deployed in WSN. We then propose a set of enhancements that are aimed to mitigate the ill-effects of these factors. We pick three protocols, namely, Flooding, AODV, and Geographic routing as candidates for this study. Using TOSSIM, we perform a detailed study of these protocols and the proposed enhancements. This study serves several purposes. First, it helps us to quantify the detrimental effects of these factors. Second, it helps us to quantify the extent to which our proposed enhancements improves packet delivery performance. Concretely, we show that using Geographic routing in a WSN with 225 nodes spread over 150 feet x 150 feet, the proposed enhancements yield a 23-fold improvement in packet delivery performance over the baseline. Further, the enhancements result in fairness (measured by the number of messages received from each node at the destination). Lastly, we show that the overhead (in terms of retransmissions, acknowledgement messages, and control messages) is reasonable