¹ Lecturer, Asian University of Bangladesh, Dhaka, Bangladesh.
² Assistant Professor, IICT, BUET, Dhaka, Bangladesh.

Jamming attack is a serious security threat for Wireless Sensor Network (WSN) in which adversaries intentionally emit radio frequency signals to corrupt ongoing transmission. Several anti-jamming techniques have been devised as countermeasures against jamming attacks. These techniques detect jamming relying on the parameters such as Packet Delivery Ratio (PDR), Packet Send Ratio (PSR), Received Signal Strength Indication (RSSI) and Clear Channel Assessment (CCA). On the other hand, energy efficiency is the major issue for WSN and it is a dominating factor for network lifetime. To prolong network lifetime, WSN is organized into clusters where each cluster head transmits aggregated data to the base station directly or using multi-hop. This paper focuses on jamming attack at the network layer in a clustering based WSN. Jamming attack in a clustered WSN affects drastically and makes clusters ineffective. As a result, WSN may experience delay in transmission, and reduction in network throughput. To overcome jamming attacks, we propose an effective jamming localizing scheme where parameters such as Jamming Signal Strength (JSS), PDR, etc., are considered in detecting jamming attacks. To continue transmission in presence of jamming, we also propose a cluster-based channel assignment technique to avoid the channels that are thwarting transmission efficiency. The simulation results reveal the accuracy of our proposed scheme in identifying jamming region, reduction in packet loss due to jammer's presence, and better throughput.