Uros Pesovic

Wireless Sensor Network Wavelet Signal Processing

Application of information technologies (IT) and wireless networking will liberate people from such confinement and enable continuous real time monitoring of physiological data, which is vital for medical care. To achieve this goal, it is necessary research and development on wearable intelligent sensor devices, sensor miniaturization, signal processing, wireless transmission, and databases for these vital data. Our goal is to implement wavelet transformations in our measured system.

Implementation of IEEE 802.15.4 transceiver on software defined radio platform

Measurement of error probability parameters in IEEE 802.15.4 transmission requires clear access to all stages of commercially available IEEE 802.15.4 transceivers. Since these transceivers are realized as monolithic chips, with limited access to certain transceiver stages, we created an IEEE 802.15.4 transceiver on a Software Defined Radio (SDR) platform with clear access to all transceiver stages. Using the realized transceiver, we were able to create a system for measurement of error probability parameters in IEEE 802.15.4 transmission.

A wireless ECG sensor node based on Huffman data encoder

The paper presents design and implementation of a wireless sensor node suitable for medical applications. As physiological signals are highly redundant, the data compression algorithms (Huffmans coding) are used to save energy and improve the node performance. Design is based on the ARM Cortex M1 processor and implemented in FPGA.

Performance analysis of improved ZigBee wireless network by simulation

In this paper we analyze performance of IEEE 802.15.4/ZigBee wireless networks in order to use these networks for transmitting different data for medical purposes such as ECG, body temperature, acceleration, etc. The aim of study is to improve efficiency of ZigBee standard by variable time and length of data transmit. The original run-length coded method is described.

Advanced wireless sensor nodes and networks for agricultural applications

A review of advanced wireless sensor nodes, networks, and applications in precision agriculture has been presented. Features of several commercial and prototype sensor node platforms designed and implemented for agricultural applications have been described. Basics of sensor network protocols and topologies have been reviewed together with numerous applications. Advanced machine learning approaches in this field (especially, Kernel Methods, Gaussian Processes, and Deep Neural Networks) have also been discussed.

Error Probability Model for IEEE 802.15.4 Wireless Communication

Wireless transmission compliant to IEEE 802.15.4 standard can be significantly affected by background noise, multipath fading and interference from other radio sources. The influence of such disturbances is most commonly expressed in a form of error probability statistics. Accurate analytical error probability model is hard to acquire, since IEEE 802.15.4 standard uses imperfect spreading sequences. Some prior works in this field tend to idealize these imperfect spreading sequences in order to simplify calculations for error probability parameters. This paper presents an analytical error probability model for IEEE 802.15.4 communication in Rician fading channel, which uses original imperfect spreading sequences without their idealization. Proposed error probability model consists of mutually dependent chip, symbol, bit and packet error probability models. Presented theoretical results are confirmed by independent numerical simulation of IEEE 802.15.4 transmission through Rician fading channel according to the Monte Carlo method.

Protothreads concept in embedded systems

The problem of concurrency in embedded systems, as well as the implementation of the protothreads are shown in this paper. Having limited system resources, especially small amount of memory, the concept of threads presented with modern operating systems is not applicable with embedded systems. Because of that, the protothreads were developed, very light threads that share single stack. They are implemented as separate C libraries or as an upgrade of existing operating system for embedded systems. As a practical implementation, the system with two protothreads that concurrently access the resources of microcontroller was developed. It is shown that the running time in case of using protothreads is greater than without them, which can be explained by lack of process scheduler.

TEDS specification for IEEE 1451.0 smart Transducer

IEEE 1451.0 standard enables independence of transducer to some degree in their functionality. TEDS represents electronic form of documents for storing all necessary data on smart transducers needed for independently executing action on the transducer. In this paper, realization of TEDS was presented on the mbed platform which was based on 32-bit ARM Cortex M3microcontroller. In paper, elements used for making TEDS structure and methods for read data from stored TEDS were described.

Concept of read data method according to IEEE 1451.0 standard using CC430F5137 microcontroller

Sensor devices are characterized by many constraints due to the nature of their use in many different environments. One of the main challenges in the development of autonomous sensing devices is the optimization of energy consumption. Therefore it is desirable to use low power microcontrollers for developing devices if it is possible also to satisfy other requirements. In addition, new trends in today technology require some intelligence of measuring devices in order to make the transducer more independent from human factors and to establish access to devices and their communication in much easier way. For this purpose standard IEEE 1451.0 was introduced, that defines common rules for smart transducers, regardless of the used equipment. This paper presents an example of data transmission in case of system based on low-power microcontroller CC430F5137 according to the smart transducer concept.

Hardware-software platform for object identification in IEEE 802.15.4 wireless networks

In this paper is presented the system for identification of objects in wireless sensor networks. Hardware of the system is consisted of sensor plate based on technology of capacitive detection of finger touch, wireless transceiver that sends its identification number when finger touch is detected, and server part which stores and processes data. Software of the system is composed of PC application that monitors nodes activities, identifies them, and performs certain statistical calculations.