QoS Performance Evaluation for Wireless Sensor Networks: The AQUASENSE Approach

The AQUASENSE project is a multi-site Innovative Training Network (ITN) that focuses on water and food quality monitoring by using Internet of Things (IoT) technologies. In this paper, we present the communication system that is suitable for supporting the pollution scenarios examined in the AQUASENSE project. The proposed system has been designed and developed in the SimuLTE/OMNeT++ simulation for simulating an LTE network infrastructure connecting the Wireless Sensors Network (WSN) with a remote server, where data are collected.

In this frame two network topologies are studied: Scenario A, a single-hop (one-tier) network, which represents a multi-cell network where multiple sensors are associated with different base stations, sending water measurements to the remote server through them, and Scenario B, a two-tier network, which is again a multi-cell network, but this time multiple sensors are associated to local aggregators, which first collect and aggregate the measurements and then send them to the remote server through the LTE base stations.

For these topologies, from the network perspective, delay and goodput parameters are studied as representative performance indices in two conditions: (i) periodic monitoring, where the data are transmitted to the server at larger intervals (every 1 or 2 seconds), and (ii) alarm monitoring, where the data are transmitted more often (every 0.5 or 1 second); and by varying the number of sensors to demonstrate the scalability of the different approaches. Besides these overall network performances, from the application perspective, to evaluate the efficiency of the system we implemented a monitoring of river pollution by simulating the collection of pH measurements from sensors and evaluated the performance in terms of reconstructing the pollution pattern at the server side in the two different network topologies (Scenario A and Scenario B).