Showing papers by "Luigi Alfredo Grieco published in 2008"
21 May 2008
TL;DR: This paper proposes a real-time communication architecture based on the leading wireless 802.11 technology and on thereal-time networking framework RTnet, and shows that a proper tuning of system parameters can ensure robust real- time wireless communications.
Abstract: Networked control systems (NCSs) exploit a packet switching network to fulfill complex control tasks without cumbersome point-to-point wiring infrastructures. But their performances are greatly influenced by time-varying packet delays and losses due to the communication system. As a consequence, real time operating systems are usually employed at NCS nodes to timely serve events scheduled by control applications. So far NCS issues have been mainly investigated assuming a wired network infrastructure. Anyway the trend is toward wireless communications. For these reasons, this paper proposes a real-time communication architecture based on the leading wireless 802.11 technology and on the real-time networking framework RTnet. The QoS offered by the proposed system, in terms of packet loss ratio and end-to-end delay, has been experimentally evaluated by varying protocol parameters. Results show that a proper tuning of system parameters can ensure robust real-time wireless communications. Thus, the present work can be considered an important step toward the design of a wireless networked control system.
22 citations
03 Oct 2008
TL;DR: A novel experimental implementation of a TDMA scheme over 802.11 MAC, based on the hard real-time networking framework RTnet and on the Xenomai real- time task scheduler is proposed, and preliminary results have shown that, using the proposed approach, transmission delays smaller than 10 ms and packet loss rates smaller than 0.5% can be achieved.
Abstract: The recent interest for wireless networked control systems has boosted new research activities on real-time 802.11-based communications. In fact, due to their versatility, wireless LANs can be exploited as infrastructure in this kind of control systems, but changes to channel access techniques are required. To this aim, we propose a novel experimental implementation of a TDMA scheme over 802.11 MAC, based on the hard real-time networking framework RTnet and on the Xenomai real-time task scheduler. Preliminary results have shown that, using the proposed approach, transmission delays smaller than 10 ms and packet loss rates smaller than 0.5% can be achieved.
16 citations
25 Jul 2008
TL;DR: The Balanced Incomplete Block Design theory has been exploited to develop a new MAC protocol for wireless ad hoc networks using directional antennas that can provide a high number of concurrent communications, depending on the number of directional antennas mounted on each node, and great fairness in bandwidth sharing.
Abstract: The use of directional antennas in wireless ad hoc networks can significantly improve global performance due to a high spatial channel reuse. Nevertheless, its introduction poses new location dependent problems related to the MAC protocol. In this paper, the Balanced Incomplete Block Design theory has been exploited to develop a new MAC protocol for wireless ad hoc networks using directional antennas. The protocol is highly scalable. Moreover, preliminary simulation results show that it can provide a high number of concurrent communications, depending on the number of directional antennas mounted on each node, and great fairness in bandwidth sharing.
3 citations