Detecting Transmission Power Misbehaviour in Wi-Fi Networks

In Wi-Fi networks, transmission (TX) power levels are constrained by regulatory limits. However, the emergence of flexible MAC drivers allows the easy modification of PHY and MAC layer parameters. This has enabled users to attempt to violate these limits. Such actions, which we refer to as TX power misbehaviour, allow users to achieve higher throughput due to the capture effect. Detecting this type of misbehaviour is challenging because of the inability to directly measure the TX power of a user's device. Therefore, in this paper, we propose detection methods for (a) determining if the TX power violates regulatory limits and (b) estimating the TX power value. Separate methods are proposed for single and multi-rate modes of operation. Simulation results verify that the proposed methods may be successfully used to detect TX power misbehaviour. Therefore, they can be implemented in a general misbehaviour detection and reaction architecture, also presented in this paper.