Cognitive Networks: Towards Self-Aware Networks

11.5. Attacks on Cognitive Networks

We define an attack on cognitive networks as any activity that results in (a) unacceptable interference to the licensed primary users or (b) missed opportunities for secondary users. An attack is considered strong if it involves a minimal number of adversaries performing minimal operations but causing maximum damage/loss to the primary and or secondary users in the network. In this section we describe attacks on various layers of cognitive networks. Most of the attacks we describe make use of one or more reliability issues we pointed out in the previous section. We consider five layers in the protocol stack, namely, the physical layer, link layer, network layer, transport layer and application layer. In addition to the attacks that are specific to a given layer, we also discuss some cross-layer attacks that can be applied at one layer to affect at another layer.

11.5.1. Physical Layer Attacks

The physical layer is the most basic layer in the protocol stack. It provides the means of transmitting raw signals over the transmission medium. The physical layer determines the bit rate, channel capacity, bandwidth and maximum throughput of the connection. In cognitive networks, the physical layer has the capability to transmit at various frequencies across most of the spectrum band. This makes the physical layer in cognitive networks more complex compared to conventional wireless networks ^[]. Therefore, when transmission from one frequency band is ...