A Comparative Analysis of Buffer Management Algorithms for Delay Tolerant Wireless Sensor Networks

One of the challenges in Delay Tolerant Wireless Sensor Networks (DT-WSN), is to handle situations where the available buffer space is insufficient- the buffer management problem. Although several buffer management algorithms have been proposed for DT-WSNs, to the best of our knowledge, there is no comprehensive study on the effects different factors have on their performance, and which evaluates the relative performance of these algorithms in different contexts. This paper evaluates in a fixed-factor factorial experiment the performance in terms of latency and Quality of Information (QoI) of four representative buffer management algorithms for DT-WSNs; two traditional, FiFO and Random, and two QoI-based algorithms- one proposed by Humber and Ngai and the SmartGap algorithm. The evaluation suggests that the buffer management algorithm in combination with employed routing protocol and the sensor node buffer sizes have a significant impact on latency, while the obtained QoI rather depends on the characteristics of the transported data and the routing protocol, provided a single-copy routing protocol is used. Moreover, the evaluation suggests that QoI-based buffer management algorithms do offer improved QoI, with an 31% improvement in MAE for SmartGap compared to FIFO. However, they do so at the expense of higher latency, with SmartGap giving a 60% higher latency than FIFO on average.