Publication

Abstract : In Wireless Sensor Networks (WSN) jamming is a type of denial of service attack for which Frequency Hopping Spread Spectrum (FHSS) can be used as a countermeasure. This technique makes use of a fixed hopping pattern with several hops per second and has a limitation that once the attacker comes to know about the fixed hopping pattern that is used in the network, he will be able to capture the entire network. The objective of this paper is to propose a novel technique which uses twenty hopping patterns with six hops in each pattern, which changes adaptively for different time instants. Each pattern is generated such that it has three odd and three even frequency channels, successive channels are not placed together. These twenty patterns are stored in all nodes along with the hundred seed values, and based on these seed values ten patterns are arranged for hopping using random pattern table. The performance of the technique is evaluated in terms of probability of matching symbols. Since the attacker will not be aware of the patterns used in the network, the probability of matching the symbols will be less, even if the attacker finds out the pattern that is used at an instant, he will be able to retrieve only the symbols that is hopped using that particular pattern and not the entire message, which shows that the proposed technique is effective.