Improving selfishness detection in reputation protocols for cooperative mobile ad-hoc networks

MCN-MR (Multi-hop Cellular Network - Mobile Relay) has been proposed as a promising technology for future Beyond 3G and 4G systems due to its foreseen capacity to increase transmission rates and provide homogeneous quality of service levels in the service area. To this aim, mobile nodes are required to cooperate in the relaying of information of other nodes. As a result, selfish nodes refusing to relay packets can have damaging effects on the overall multi-hop connectivity of MCN-MR networks. Different reputation protocols have been already proposed to cope with selfishness in mobile ad-hoc networks, but they tend to overestimate the selfish behavior of nodes, due to the effects of radio errors or packet collisions that can be mistaken for intentional packet drops. Thus, the availability of valid multi-hop routes usable by nodes is reduced. In this context, this paper proposes and evaluates two techniques that improve the operation and ability to accurately detect selfish nodes of the watchdog detection mechanism that is generally employed in reputation based selfishness prevention protocols.