Detection of side-channel communication in ad hoc networks using request to send (RTS) messages

Wireless communication channels using the 802.11 protocol adopt the RTS/CTS mechanism to avoid collisions in the channel and to increase throughput. In a perfect scenario with no data loss, there exists a linear relationship between number of the valid frames received and the RTS received in the receiver. We propose a detection mechanism that keeps track of the rate of RTS per application data frames received where any deviation from its expected value could trigger an alarm for a possible side-channel communication hidden by error frames. Several scenarios are simulated using QualNet simulator by varying the parameters to study the relationship between the good frames and the RTS. Based on the data collected we submit that this rate is a viable metric for detection.