Trading transport timeliness and reliability for efficiency in wireless sensor networks

A key task in wireless sensor networks is to deliver information from sensor nodes to the sink. Many applications require the delivery to be reliable and timely. However, increasing reliability/timeliness comes at the cost of higher energy consumption as in both cases additional messages have to be sent: Retransmissions to increase reliability and information delivery via a second, faster path to ensure timeliness. Existing transport protocols either over- or under-provide reliability and/or timeliness and lack optimized efficiency. This work aims in tuning reliability and timeliness in composition for a maximized efficiency. Our approach´s takes the reliability/timeliness requirements as input and features a message efficiency that optimally meets user requirements. Information transport proceeds in two steps in a fully distributed way: (i) Finding the optimal number of retransmissions on a per hop basis with delay compensation, and (ii) path split and/or replication if reliability or timeliness requirements are violated. We validate the approach viability through extensive simulations for a wide range of requirements and network conditions.