IEEE 802.11ax Spatial Reuse Improvement: An Interference-Based Channel Access Algorithm

Wi-Fi is the dominant way of connecting indoor mobile devices to the Internet. The main reason behind the huge adoption of this technology is the simplicity of IEEE 802.11 protocols which in turn offer low-cost ownership and maintenance combined with the ability to offer high data rates to end users. The increasing demand in traffic volumes leads to the continuous deployment of access points (APs) resulting in densification of the IEEE 802.11 networks. This fact, instead of enhancing the efficiency of wireless local area networks (WLANs) degrades their overall performance due to cochannel interference between overlapped basic services sets (OBSSs). One of the main goals of the under-development IEEE 802.11ax amendment is to address the WLAN densification problem by improving spatial reuse (SR). In this article we present and evaluate a channel access algorithm, which considers the expected interference that nodes will suffer by a concurrent transmission so to decide if transmission or defer will take place. It is shown that the proposed interference based dynamic channel algorithm (IB-DCA) offers significant SR performance gains comparing to the existing channel access algorithms, in terms of the station mean data rate, for all the stations in a IEEE 802.11ax dense deployment

STEM Learning and Career Orientation via IoT Hands-on Activities in Secondary Education

This work studies the influence of IoT-driven educational activities and tools (software, hardware and educational material) in STEM education as well as their role as STEM related career enablers to young boys and girls. The study builds on previous related results and applies to over 60 young students that are involved in hands-on learning activities in the context of a summer school. The analysis is based on especially designed close-ended and open-ended questionnaires as well as in-class observations and focuses on age and gender aspects. The results confirm the overall positive stance of the students on the educational activities and show that the provided tools under consideration are well accepted and effectively used. Furthermore, students’ choices regarding prospective future careers reveal that their views on STEM fields and related professions have significantly been enriched through their participation in the summer school

A survey of strategies for communication networks to protect against large-scale natural disasters

Recent natural disasters have revealed that emergency networks presently cannot disseminate the necessary disaster information, making it difficult to deploy and coordinate relief operations. These disasters have reinforced the knowledge that telecommunication networks constitute a critical infrastructure of our society, and the urgency in establishing protection mechanisms against disaster-based disruptions. Hence, it is important to have emergency networks able to maintain sustainable communication in disaster areas. Moreover, the network architecture should be designed so that network connectivity is maintained among nodes outside of the impacted area, while ensuring that services for costumers not in the affected area suffer minimal impact. As a first step towards achieving disaster resilience, the RECODIS project was formed, and its Working Group 1 members conducted a comprehensive literature survey on “strategies for communication networks to protect against large-scale natural disasters,” which is summarized in this article