Abstract
A data-dependent sensor MAC protocol and a cross-layered fusion rule, that exploits the MAC timing information, are proposed for distributed detection in sensor networks. In this system, each sensor first makes a local decision at the beginning of each observation period and transmits it to the fusion over a random access channel. Based on the slotted ALOHA random access protocol, we derive a transmission control function that assigns transmission probabilities to sensors based on the reliability of their local decisions. By doing so, the packet arrival time at the fusion center may embed soft information regarding the sensors' observations and may be exploited to reduce the error probability at the fusion center. We consider two observation models: in Case I, each sensor makes a new observation in each time slot; while in Case II, only one observation is made at the beginning of each observation period. We show, through numerical simulations, that the proposed schemes outperform those without cross-layered transmission and fusion strategies. ©2008 IEEE.