Routing with Minimized Slot Misordering for Delay Mitigation in TDMA based Sensor Networks

This paper presents a minimized slot misordered routing (MSMR) technique for end-to-end delay mitigation in sensor networks with TDMA medium access control. MSMR targets delay sensitive and event based sensor network applications such as tactical surveillance, intrusion detection, and industrial process monitoring. Delay reduction in MSMR is accomplished by computing least cost routes with a link cost formulation based on the degree of misordering of the TDMA slots of nodes across a link. It is shown that in large sensor networks with low to moderate event generation rates, the proposed MSMR technique can significantly reduce the end-to-end event reporting delay compared to naive minimum-hop routing. The paper also analyzes the energy-delay tradeoff for MSMR It is demonstrated that due to its larger hop counts, at higher event rates, MSMR may give rise to undesirable queuing effects. To mitigate this, a balanced MSMR protocol that can balance queuing delay and slot misordering delay is also proposed. Results demonstrate that for applications with higher event rates, the Balanced MSMR can achieve better delay performance than MSMR.