Browsing by Author "Royo, Fernando"
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- BANMAC: an opportunistic MAC protocol for reliable communications in body area networksPublication . Prabh, K. Shashi; Royo, Fernando; Tennina, Stefano; Olivares, TeresaWe consider reliable communications in Body Area Networks (BAN), where a set of nodes placed on human body are connected using wireless links. In order to keep the Specific Absorption Rate (SAR) as low as possible for health safety reasons, these networks operate in low transmit power regime, which however, is known to be error prone. It has been observed that the fluctuations of the Received Signal Strength (RSS) at the nodes of a BAN on a moving person show certain regularities and that the magnitude of these fluctuations are significant (5 - 20 dB). In this paper, we present BANMAC, a MAC protocol that monitors and predicts the channel fluctuations and schedules transmissions opportunistically when the RSS is likely to be higher. The MAC protocol is capable of providing differentiated service and resolves co-channel interference in the event of multiple co-located BANs in a vicinity. We report the design and implementation details of BANMAC integrated with the IEEE 802.15.4 protocol stack. We present experimental data which show that the packet loss rate (PLR) of BANMAC is significantly lower as compared to that of the IEEE 802.15.4 MAC. For comparable PLR, the power consumption of BANMAC is also significantly lower than that of the IEEE 802.15.4. For co-located networks, the convergence time to find a conflict-free channel allocation was approximately 1 s for the centralized coordination mechanism and was approximately 4 s for the distributed coordination mechanism.
- Z-Monitor: A protocol analyzer for IEEE 802.15.4-based low-power wireless networksPublication . Tennina, Stefano; Gaddour, Olfa; Koubaa, Anis; Royo, Fernando; Alves, Mário; Abid, MahomedNetwork sniffers are invaluable tools for designing, testing, commissioning and running distributed embedded systems. They become even more useful if these systems build on low-power wireless networks (LoWPAN), particularly when these scale in density and/or space and impose stringent quality-of-service requirements. This paper presents Z-Monitor, a low-cost and open-source network/protocol analyzer for LoWPANs. Z-Monitor is better than existing solutions since it combines the following features all-together: it covers the most widely used LoWPAN protocols, namely IEEE 802.15.4, 6LoWPAN, RPL and ZigBee; packet sniffing can be performed by any IEEE 802.15.4-compliant node, e.g., TelosB or MicaZ, requiring no extra hardware; the code is in Java (host PC), so it is OS-agnostic, and is freely available as open-source; Z-Monitor provides an user-friendly graphical user interface and a complete set of functionalities; nonetheless, Z-Monitor software architecture and programming approach are modular, so it is easily adaptable and extensible. We demonstrate and validate Z-Monitor in several LoWPAN network scenarios/settings and sites, ranging from a small-scale laboratory test-bed to a 400+ real-world deployment.