Experimental protocols and testbed for radio link quality evaluation over the freshwater

Abstract

Estimating a radio link quality for WSNs "Wireless Sensor Networks" becomes a big challenge when these networks are deployed in harsh or hostile environment. The quality of a radio link is a useful information for higher layer protocols as it has an impact on the network performance. The harsh or hostile outdoor conditions have a strong impact on signal propagation and make communication difficult or unreliable. Hence, deploying a wireless sensor network in such an environment requires a full knowledge of radio channel characteristics provided by the hardware designed to tackle the deployment. This paper describes a novel experimental testbed platform and a method to estimate the radio link quality and to determine WSN deployment parameters by using nodes shaped to the monitored site. The objective is to design a platform, independent from the environment, that can be used to estimate the radio link quality independently from the deployment context. This SDR "software defined radio" based solution will be used in this paper to estimate the parameters of an overwater radio link.

Ground Level Deployment of Wireless Sensor Networks: Experiments, Evaluation and Engineering Insight

“…Although it is well known [14,15,20,21,22,23] that the radio link in low-power WSN is very unstable because of many factors such as the radio properties or the propagation environment, the results presented in this section show that, at the ground level, the radio links quality (measured by the PRR and RSSI values) are more severely affected by such environment. This must be taken into account, not only during the deployment of such networks, but also for designing communication protocols.…”

“…The temperature at ground level can also be an explanation for this result. Indeed, several studies [21,22,23] show that, the higher is the temperature, the lower is the quality of the link, because of the thermal noise. In our case, with sensors deployed on a road, often in full sunlight, the temperature at ground level was significantly higher than the temperature for the deployment at height.…”

“…Moreover, not only spatial properties of link have been observed, but also seasonal properties [21,22,23]. In [22,23], the authors evaluated the impact of the weather on the link quality in a WSN.…”

“…In [22], the authors designed a low-cost experimental infrastructure to vary the on-board temperature of sensor nodes and their results also show a correlation between link quality and temperature. In [21], the authors proposed a new platform and used it to estimate the parameters of an over-water radio link, through two experiments: one conducted in the morning and another in the afternoon. From the morning to the afternoon experiment, the temperature and the relative humidity reduced by about 2 °C and 25% respectively.…”

“…Their results shown an increasing of the radio range from 40 m in the morning to 70 m in the afternoon. The results presented in [21,22,23] show a poor link quality in presence of high temperature. In our case, since temperature is higher at ground level, this brings a negative impact on link quality compared to links placed higher above ground.…”