A Trust Evaluation Method for Node Cooperation in Mobile Ad Hoc Networks

In ad hoc networks, node misbehaviors due to selfish or malicious reasons can significantly degrade the performance of ad hoc networks. Previously, we proposed a trust-based incentive model on a self-policing mechanism to make nodes evaluate the trust of their neighbor locally (Kun and Meng, 2007). That approach can mitigate contamination by direct observation and the use of second-hand information available. However, one situation hasn´t been considered that the secondhand information can be spurious, which raises the questions of how to incorporate it in a safe way and whether to propagate it. In this study, we adopt a trust evaluation method with a trust scaling factor on that trust-based incentive model to relieve the influence of fake second-hand information on the accuracy of trust value. Performance by simulation reveals that in the case of existing malicious nodes, the enhanced trusted dynamic source routing (ET-DSR) with proposed trust evaluation method performs better than T-DSR in terms of packet successful delivery ratio and mean number of packets dropped. Meanwhile, ET-DSR is more suitable for large scale networks than T-DSR due to the introduction of trust scaling factor.