The present paper presents a Markov Chain model of polling in noisy multi-hop systems typical of Power Line Communications (PLC) as well as of other systems. The model includes the transmission of a Backwards Error Indication Packet (BEIP) to the master when the transmission is blocked in one of the downstream hops as well as the possibility to reduce the global time-out value below that strictly necessary to avoid having two simultaneous polls within the system. Two Case Studies are presented; the OPERA PLC access broadband specification and a narrow band PLC based Automatic Meter Reading (AMR) system. Explicit formulas for the delay in these systems and curves representing the behavior of the studied cases are given.
Joseph M. Selga, Agustín Zaballos, Jaume Ab