Providing reliable and timely communication in wireless industrial systems requires careful design of error control schemes able to tackle the bit error patterns typically occurring in these enviro ...

This paper present a empirical measurement comparison study of ZigBee and Bluetooth. The parameters investigated are power consumption, packet-error-rate or retransmissions and distance in differen ...

The use of wireless communication technologies in the industry offer several advantages. One advantage is the ability to deploy sensors where they previously could not easily be deployed, for instance on parts that rotate. To use wireless communication in industrial control loops, demands on reliability and latency requirements has to be met. This in an environment that may be harsh for radio communication. This work presents a reliable, low latency wireless communication system. The system is used in a wireless thyristor control loop in a hydro power plant generator. The wireless communication is based on Bluetooth radio modules. The work shows a latency analysis together with empirical hardware based latency and packet error rate measurements. The background noise of a hydro power plant station is also investigated. The average latency between the Bluetooth modules for the proposed system is 5.09 ms. The packet error rate is 0.00288 for the wireless low latency control system deployed in a hydro power plant.

This paper presents a realistic model of the radio energy consumption for Bluetooth-equipped sensor nodes used in a low-duty-cycle network. The model is based on empirical energy consumption measurements of Bluetooth modules. This model will give users the possibility to optimize their radio communication with respect to energy consumption while sustaining the data rate. This paper shows that transmission power cannot always be directly related to energy consumption. Measurements indicate that, when the transmission power ranges from -5 to +10 dBm, the difference in consumed energy can be detected for each transmission peak in the sniff peak. However, the change is negligible for the overall energy consumption. The nonlinear behavior of the idle state for both master and slave when increasing the interval and number of attempts is presented. The energy consumption for a master node is in direct relation to the number of slaves and will increase by approximately 50% of the consumption of one slave per additional slave, regardless of the radio setting.

This paper presents a time synchronized wireless ECG sensor network with reliable data communication. Wireless ECG systems are a popular research area where several research groups have presented point-to-point solutions. Alongside the wireless ECG research, the wireless sensor network research has created an increasing interest for secure, low power and predictable network applications. Combining these research areas is a natural step for the evolution of secure wireless monitoring of physiological parameters. In this study the Bluetooth radio standard has been chosen for its versatility. This paper focuses on both the hardware and the software development for a functional multihop ECG network using Bluetooth. The presented wireless ECG network is reliable up to link loss and is easily configured to send more or different types of signals. The system has been tested and verified for secure multihop communication.

Wireless communication in industrial, scientific and medical applications have several benefits. The main benefits when using wireless technologies include ease-of-deployment, the simplicity to introduce new units into the network and mobility. However it also put higher demands on the communication, including reliability and predictability compared to wired communication. The reliability issues correlate to the radio communication and the possibility to ensure that the user data is received, and within the time frame of the system requirements. This doctoral thesis presents an empirical measurement approach to investigate and model the behaviour linked to reliability and predictability. The focus of the work presented is energy consumption, packet-error-rate and latency studies. This is performed for various radio technologies and standards in (radio?) harsh environments. The main contributions of this thesis are the measurements platforms and procedures that have been developed to meet the requirements to investigate modern radio technologies in terms of predictability and reliability. This thesis show that it is possible to predict wireless communication in radio harsh environments. However it is necessary to determine the characteristics of the environment to be able to choose a suitable radio technology. The measurement procedures presented in this thesis alongside the platform developed enable these types of investigations. In this thesis a model of the energy consumption for a Bluetooth radio in low-duty-cycle applications with point-to-multipoint communication is presented. The measurements show that distance and transmission power will not effect the energy consumption for a Bluetooth nor ZigBee module. However the packet-error-rate and number of retransmissions will affect the overall energy consumption, and these parameters can be correlated to distance and foremost the environmental characteristics. This thesis also presents two application-based solutions, a time synchronized ECG network with reliable data communication as well as a low-latency wireless I/O for a hydro plant.