|Wireless Sensor Network (WSN) is a wireless-oriented form of communication largely used for outdoor applications, such as environmental monitoring and military surveillance. Therefore, a jamming attack is one of the denial of service attacks (DOS) that may take place by jamming the communication channel, making communication between genuine sensor nodes difficult or even impossible. Several studies have been carried out to develop countermeasures against jamming attacks, utilising parameters such as Packet Delivery Ratio (PDR), Packet Send Ratio (PSR), Received Signal Strength Indication (RSSI) and Clear Channel Assessment (CCA). The accuracy of the parameters used is very important for developing successful countermeasures against jamming attacks. Consequently, the focus in this study is to examine the effect of a jamming attack that was generated by one or more wireless sensor network nodes on PDR, PSR and RSSI, and look at the enhancements that can be made on Packet Delivery Ratio by altering the value of CCA on sender nodes.
The experiment was performed using XBee RF and K-mote devices configured as jammers by disabling the CSMA protocol. It was performed in a non-isolated room in order to emulate a real-life environment.
Two scenarios were carried out in this study. The first scenario aimed to study RSSI, PSR and PDR values with a fixed CCA value, and the second scenario studied the effect of CCA on PDR value.
The experiment showed that the RSSI value measured by XBee RF inflated in the presence of noise. This fact has to be considered when RSSI is utilised in jamming attack counter measures. Further, it has been observed that the PDR value is distressed by jamming because genuine packets collide with jammers’ packets and increase the power of the sent packets without considering that the distance will not be enough to enhance the PDR value. This study demonstrates that changing the CCA threshold value on the XBee RF module influences the Packet Delivery Ratio (PDR) value in the presence of jamming.