Defending Wireless Sensor Networks from Jamming Attacks

Wireless sensor networks (WSNs) are used in many applications which often include the monitoring and recording of sensitive information. Hence, their critical importance raises many security concerns. In the context of WSNs, jamming is the type of attack which interferes with the radio frequencies used by network nodes. In the event that an attacker uses a rather powerful jamming source, disruptions of WSNs proper function are likely to occur. As a result, the use of countermeasures against jamming in WSN environments is of immense importance. The main contribution of this article is the discussion of various defence methods against jamming that would allow a WSN to survive and work properly in a hostile jamming environment. Our focus is on frequency hopping spread spectrum (FHSS) and direct sequence spread spectrum (DSSS), two of the most effective countermeasures against jamming. We suggest the use of a specific FHSS technique in 5 GHz band with 55 frequency channels wherein the channel sequence is generated using a secret word, known only to the sink and the sensor nodes, as a seed. Each channel uses DSSS modulation with 16 bit Pseudo Noise (PN) code, which derives from the same secret word used for FHSS channel generation.