Control channel hopping for avoidance of scrambling attacks in IEEE 802.16 systems

A scrambling attack is a form of intentional physical jamming attack. A scrambling attack attempts to disrupt specific intervals, such as a control channel. In IEEE 802.16 systems such as WiBro and WiMax, the control channel is located at the beginning of a frame, which has a fixed duration and empty intervals of a receive transition gap (RTG) within its duration. Hostile attackers can easily detect the start time of frames and jam the control channel using a scrambling attack due to these features of IEEE 802.16 systems. In this paper, we propose an approach to prevent the disruption of the control channel from this scrambling attack in IEEE 802.16 systems. The control channel, including frame control header (FCH), downlink map (DL-MAP), and uplink map (UL-MAP), is hopped based on a common hopping sequence to a different symbol index in the downlink at each frame. Simulations show that the control channel of the proposed scheme survives against the scrambling attack and an additional random pulse jamming attack in the time domain.