中文摘要：

大量具备短距离通信能力的智能设备的出现推动了无线自组网应用的迅速发展．但在许多实际应用环境中，节点移动、网络稀疏或信号衰减等各种原因通常导致形成的网络大部分时间不连通．传统的移动自组织网络传输模式要求通信源和目标节点之间存在至少一条完整的路径，因而无法在这类环境中运行．机会网络利用节点移动形成的通信机会逐跳传输消息，以“存储-携带-转发”的路由模式实现节点间通信，这种完全不同于传统网络通信模式的新兴组网方式引起了研究界极大的兴趣．首先介绍机会网络的概念和理论基础，并给出了当前机会网络的一些典型应用，然后详细阐述了机会网络研究的热点问题，包括机会转发机制、移动模型和基于机会通信的数据分发和检索等，并阿要叙述了机会网络的通信中间件、协作和安全机制以及机会网络新的应用等其他研究问题，最后进行总结并展望了机会网络未来一段时间内的研究重点．

英文摘要：

The appearance of plenty of intelligent devices equipped for short-range wireless communications boosts the fast rise of wireless ad hoc networks application. However, in many realistic application environments, nodes form a disconnected network for most of the time due to nodal mobility, low density, lossy link, etc. Conventional communication model of mobile ad hoc network （MANET） requires at least one path existing from source to destination nodes, which results in communication failure in these scenarios. Opportunistic networks utilize the communication opportunities arising from node movement to forward messages in a hop-by-hop way, and implement communications between nodes based on the ＂store-carry-forward＂ routing pattern. This networking approach, totally different from the traditional communication model, captures great interests from researchers. This paper first introduces the conceptions and theories of opportunistic networks and some current typical applications. Then it elaborates the popular research problems including opportunistic forwarding mechanism, mobility model and opportunistic data dissemination and retrieval. Some other interesting research points such as communication middleware, cooperation and security problem and new applications are stated briefly. Finally, the paper concludes and looks forward to the possible research focuses for opportunistic networks in the future.