Simulating node selfishness in opportunistic networks

In situations where Internet connectivity is not available, opportunistic networks exploit the encounters between mobile human-carried devices for exchanging information. When people encounter each other, their handheld devices can communicate wirelessly and in a cooperative way using the encounter opportunities for forwarding their messages. However, in the real world, most of the nodes exhibit selfish behaviors mostly to conserve the limited buffer and power resources. As such, for ensuring a fair delivery, node selfishness should be taken into account. In this paper, we study the impact of node selfishness on the system throughput and delay of opportunistic communications. Through extensive simulations, we evaluate the system performances by utilizing experimental human mobility traces with different communication patterns. Our results show that the message delivery ratio decreases and the end-to-end average latency increases as the percentage of selfish nodes increases for all the routing protocols considered. However, the social-based forwarding rules are able to better manage node selfishness.