Dependable Information Exchange for the Next Generation Mobile Cyber-Physical Systems

Mobile cyber-physical systems (M-CPSs) are envisaged as an integral part of our digital future. Dependability of M-CPSs is subject to timely, reliable, and secure information exchange among M-CPS entities. Information exchange provisioning in such systems is conventionally built with sole reliance on wireless connectivity. The conventional approaches, however, fail to efficiently exploit dynamism and heterogeneity, and to incorporate computing/cooperation as alternative system-wide tools for information exchange. To address these issues, we approach M-CPSs dependability from the information exchange perspective and define dependable-exchange-of-information (DeX) indicating collective M-CPS capability of information exchange provisioning. We then propose a cloud-based architecture for DeX provisioning as a service to facilitate versatile development of dependable M-CPSs

On the Diversity Order and Coding Gain of Multi-Source Multi-Relay Cooperative Wireless Networks with Binary Network Coding

In this paper, a multi-source multi-relay cooperative wireless network with binary modulation and binary network coding is studied. The system model encompasses: i) a demodulate-and-forward protocol at the relays, where the received packets are forwarded regardless of their reliability; and ii) a maximum-likelihood optimum demodulator at the destination, which accounts for possible demodulations errors at the relays. An asymptotically-tight and closed-form expression of the end-to-end error probability is derived, which clearly showcases diversity order and coding gain of each source. Unlike other papers available in the literature, the proposed framework has three main distinguishable features: i) it is useful for general network topologies and arbitrary binary encoding vectors; ii) it shows how network code and two-hop forwarding protocol affect diversity order and coding gain; and ii) it accounts for realistic fading channels and demodulation errors at the relays. The framework provides three main conclusions: i) each source achieves a diversity order equal to the separation vector of the network code; ii) the coding gain of each source decreases with the number of mixed packets at the relays; and iii) if the destination cannot take into account demodulation errors at the relays, it loses approximately half of the diversity order.Comment: 35 pages, submitted as a Journal Pape