Search

Over the past few years, the use of wireless sensor networks in a range of Internet of Things (IoT) scenarios has grown in popularity. Since IoT sensor devices have restricted battery power, a proper IoT data aggregation approach is crucial to prolong the network lifetime. To this end, current approaches typically form a virtual aggregation backbone based on a connected dominating set or maximal independent set to utilize independent transmissions of dominators. However, they usually have a fairly long aggregation delay because the dominators become bottlenecks for receiving data from all dominatees. The problem of time-efficient data aggregation in multichannel duty-cycled IoT sensor networks is analyzed in this paper. We propose a novel aggregation approach, named LInk-delay-aware REinforcement (LIRE), leveraging active slots of sensors to explore a routing structure with pipeline links, then scheduling all transmissions in a bottom-up manner. The reinforcement schedule accelerates the aggregation by exploiting unused channels and time slots left off at every scheduling round. LIRE is evaluated in a variety of simulation scenarios through theoretical analysis and performance comparisons with a state-of-the-art scheme. The simulation results show that LIRE reduces more than 80% aggregation delay compared to the existing scheme. [ABSTRACT FROM AUTHOR]

In this paper, we present a practical public key certificate structure that is combined with an authentication protocol for roaming across different wireless Internet service providers (ISPs). The design rationale is to enable the mutual authentication between the roaming mobile device (MD) and the visited network to be locally performed without invoking the MD's home ISP. The mutual authentication ensures that the visited network has authenticity as well as a mechanism for establishing the appropriate revenue stream for the roaming MD. The proposed scheme guarantees that the overhead associated with the authentication time is significantly reduced and that the impact of this overhead on the roaming MD is also minimized, although the nested depth of the network mobility is increased. In this paper, we use analytical comparisons to show that the proposed scheme creates less overhead than that of the previous approaches in terms of security and communication performance. [ABSTRACT FROM PUBLISHER]