The IEEE 802.15.4 standard represents one of the most successful technologies for enabling low-rate wireless personal area networks (LR-WPANs). Accordingly, the properties of its protocols (at physical and MAC layers) have been widely studied in the scientific literature to derive performance bounds on throughput, delays, and frame losses. At the same time, to the best of the authors’ knowledge, a complete characterization of the frame-error-rate process, including also the correlation among loss events, is still missing. This kind of investigation is particularly relevant in noisy industrial environments, which, as well known, introduce bursty frame losses. To this end, this paper proposes a Markov model to account for the different changing conditions under which an IEEE 802.15.4 channel is seen at the MAC layer. The model is able to reproduce synthetic traces having a cumulative distribution function and an autocorrelation coefficient that closely resemble experimental measurements. In this way, it becomes a valuable tool for further refining existing theoretical models and simulation platforms for IEEE 802.15.4 LR-WPANs and for helping the designer and researcher working on industrial Internet of things.

This paper summarizes all research advancements obtained by the Polytechnic of Bari through the RES NOVAE Project activities in the field of the smart district. In this context it is important to investigate and apply new efficient technologies solutions for the building management in order to optimize the energy usage and to improve the inhabitants’ comfort. The integration of the ICT technologies and the building automation systems together with innovative renewables energy solutions is studied. Moreover, suitable control algorithms, communication protocols and measurement devices are proposed and tested to improve the efficiency of the building energy management systems.

Variable-Bit-Rate (VBR) video transmission over UMTS networks is assuming an ever growing importance, then scheduling VBR data over wireless channels attracts great interest today. This paper proposes an on-line PI control algorithm for easily and suitably scheduling interactive multimedia transmission of VBR video streams. It dynamically adapts the transmitted bit rate to the user’s actions that can suddenly and highly modify the client buffer level. The Real-time Transport Control Protocol (RTCP) packets periodically feed back the buffer level to the server for keeping the free buffer space at 50% of its capacity, so as to prevent both buffer overflow and underflow. Numerical results of different simulated scenarios show the effectiveness of the proposed controller in comparison with two well-established algorithms, enhanced with RTCP information.

This paper summarizes all research advancements obtained by the Politecnico di Bari through the RES NOVAE Project activities in the field of the smart grids. Such activities have been aimed at bringing substantial contributions in the development of smart grid in medium-voltage and low-voltage distribution systems. Since the scientific approach to smart grids is intrinsically multidisciplinary, specific researches were addressed in all the fields of electrical and information engineering that are involved in the creation of future distribution systems. The paper is organized in seven sections, each providing description of the research results developed in a specific field (power systems, communication systems, power electronics, electric measurements, circuits and systems, information processing systems, automatic control).