Event-Driven Coverage and Rate Allocation for Providing Miss-Ratio Assurances in Wireless Sensor Networks

Wireless sensor networks are often densely deployed to prolong their lifetime by rotating the subset of nodes that are put on duty. This paper addresses the following two problems: Given the required miss-ratios for multiple events, (i) which subset of nodes should be put on duty for each event to assure its event miss-ratio?, and (ii) how should those on-duty nodes encode their data with minimum overhead of source coding and maximum energy saving? We propose CORA protocol which activates sensor nodes and assigns their rates jointly based on dynamically changing probability of event occurrences. The on-duty sensor nodes are assigned different rates based on whether they are located at hot spots or not. Those sensor nodes that are located at the hot spots are made active dynamically by CORA in such a way that proportional fairness is achieved in providing their miss-ratio guarantees. Simulation results show that CORA meets event miss-ratio assurances fairly and achieves high source coding gain with negligible overhead of correlation information maintenance.