Adaptive Trust Update Frequency in MANETs

Most of the existing trust-based security schemes for MANETs compute and update the trustworthiness of the other nodes with a fixed frequency. Although this approach works well in some scenarios, some nodes may not be able to afford the periodical trust update due to the limited resources in energy and computation power. To avoid energy depletion and extend the network lifetime, trust-based security schemes need approaches to update the trust taking into account the network conditions at each node. At the same time, a trade-off in terms of packet loss rate, false positives, detection rate, and energy of nodes is needed for network performance. In this paper, we first investigate the impact of trust update frequency on energy consumption and packet loss rate. We then identify network parameters, such as packet transmission rate, packet loss rate, remaining node energy, and rate of link changes, and leverage these parameters to design an Adaptive Trust Update Frequency scheme that takes into account runtime network conditions. The evaluation of our prototype shows significant improvements in the tradeoff between energy saving and packet loss rate over traditional fixed-frequency approaches.