Queueing Model and Optimization of Packet Dropping in Real-Time Wireless Sensor Networks

We consider the problem of modeling the transmission of real-time data from a single node of a wireless sensor network to the next hop or access point. Generated packets are placed in a single position buffer and are transmitted over the wireless medium to the next hop, or they are discarded and replaced when a new data packet is generated from the sensor. To increase the percentage of packets delivered on-time to the next hop, we introduce a thresholding policy that is supported by an analytical model and it is responsible for deciding whether to transmit a data packet or drop it and transmit the next one. Our model considers the behavior at single sensor where data are generated with a Poisson process and have a fixed deadline associated to them while the impact of the other sensors is modeled through their effect on the MAC service time. However, we also evaluate the performance of the packet dropping scheme in a multi-hop sensor chain. The proposed policy leads to a higher percentage of on-time delivered packets in both scenarios.