Simulation is one of the most powerful tools we have for evaluating the performance of Opportunistic Networks. In this survey, we focus on available tools and models, compare their performance and precision and experimentally show the scalability of different simulators. We also perform a gap analysis of state-of-the-art Opportunistic Network simulations and sketch out possible further development and lines of research. This survey is targeted at students starting work and research in this area while also serving as a valuable source of information for experienced researchers.

Opportunistic networks have recently seen increasing interest in the networking community. They can serve a range of application scenarios, most of them being destination-less, i.e., without a-priori knowledge of who is the final destination of a message. In this paper, we explore the usage of data popularity for improving the efficiency of data forwarding in opportunistic networks. Whether a message will become popular or not is not known before disseminating it to users. Thus, popularity needs to be estimated in a distributed manner considering a local context. We propose Keetchi, a data forwarding protocol based on Q-Learning to give more preference to popular data rather than less popular data. Our extensive simulation comparison between Keetchi and the well known Epidemic protocol shows that the network overhead of data forwarding can be significantly reduced while keeping the delivery rate the same.

IEEE 802.15 task group 8 (IEEE 802.15.8) has been recently chartered to define PHY and MAC mechanism for wireless personal area networks (WPAN) peer aware communications (PAC) optimized for peer to peer and infrastructureless communications with fully distributed coordination. The most promising services created by IEEE 802.15.8 would be multicast communication with simultaneous membership in multiple groups, typically up to 10, in dense network topology. Most existing multicast techniques in mobile ad hoc networks (MANET) have relied upon a central coordinator to manage its multicast group and thus cannot be used for fully-distributed PAC networks. In this paper, we propose a graph-based multicast routing protocol referred to as fully-distributed multicast routing protocol (FDMRP) for IEEE 802.15.8 PAC networks. The FDMRP minimizes routing table entries and thus reduces control message overhead for its multicast group management. To balance the control message, all nodes in the network have a similar number of routing entries to manage nodes in a same multicast group. To measure the effectiveness of the proposed FDMRP against the ODMRP [10], we evaluated performance by OPNET simulator. Performance evaluation shows that the FDMRP shows less control message overhead and multicast group join latency than the ODMRP.